Unfortunately 'sudden unrealistic event in otherwise good manga' wasn't included, so I went with the 'bad drawings' instead. There's quite a lot of crappily drawn Shoujo and Josei around...

I was really torn here. If I could I would have voted for Bad/weak endings AND Uninspiring/lame characters AND Lackluster plot AND Lack of originality. Many Manga titles (especially those for the Shounen demographic) seem frequently plagued by the combination of all of these. So much so that when I find a title with only two of these failings out of four, I feel like I've found a masterpiece. But then again Manga is about the visuals as much as the storyline for me, and thankfully the average artist seems to be a lot better equipped than the average writer.

I honestly think bad endings are the largest factor in overall ruining a series for me; be it an open ended ending, a broad ending, or rushed ending, they just really ruin an overall series for me. I liked School Rumble, as an example, a lot but other than arcs and events I remember I don't recall the ending since it left no impression on me. The list goes on for many a series I have read but long forgotten about given the poor endings.

Edit: I was also reminded of Air Gear, this series had a lot of potential in the beginning and then eventually became so abstract and pointless and trying to be something extremely unique and different only to fail. The last few chapters were unbearable and here's my rendition of it.

I usualy cant relate at all to the characters
that in time makes it boring
and i drop it

an awful series i read atm is the Elminster series by ed Greenwood
Elminster is this extreamly powerfull wizard who can do pretty much whatever he wants
and if he for some reasons should fail or die...a goddess steps in and resurrects him/helps him
and not only that
he murderers everyone he deems evil...when it would have been better to take out the top in the evil organization since most of the badguys usualy work out of fear and would not have acted in this way if they would have the chance of a diffrent life
and he fucks with all the girls he come across
even his goddess

to name some manga
akumetsu
he is a deranged psycho who hurts ALOT of ppl...even if he have "justice" on his side he just goes overboard

InuYasha have lots of dangerous murderers in the goodguy team
they usualy kill and eat humans but now since they help the good side...they are good

the To Aru novels
accellerator
an evil massmurderer who gets retconned into a good guy...and the goodguys accept him right away

Toriko
a manga about killing and eating [endangered] [nonaggresive] animals for fun

hunterxhunter
have some of this shit going on too
just kill animals for sports
not1 oppose this

bad writing is part of it...but i just cant relate to murderers and those that abuse animals

bad endings . too bad theres no ' all of the above' option

Lack of originality. So many plots are the same. Some don't even have plot! And I feel you see this among all genres, but I think shoujo and shounen are the worst offenders.

For me, it's a tie between bad endings and lack of originality. Sometimes, it's so frustrating when the plot is predictable and the characters are stereotypical... wait that's another pet manga peeve! Oh well- reading manga is still my favourite hobby!

I've voted "lack of originality", but by that I meant one extremely specific flow: kindergarten level of romantic. Nosebleeds instead of erections, grabbing a feel is like an unclimbable mountain, and simple kiss meaning end of the world(and usually the manga as well).

uninteresting characters

The only deal breaker for me is characterization. It's impossible to be completely original, what a story needs is characters (this includes backstories) that really pull you in

This is why I hate shoujo, not because it's "romance" but because 99% of the MC's are pathetic brainless high school girls who've only got their "dream" of having a boyfriend in mind, and THE WHOLE PLOT IS ABOUT THIS

what kills me is when manga just goes on and on and on without advancing the plot much. Bleach and even some OP arcs really have trouble with this sometimes. I felt like the entire mermaid arc was 10 times as long as it needed to be. they were all 100x as strong as everyone else. they should have just trashed the mooks and left in a few chapters not taken months to do so.

I'd have to go with the top three as the main reason that makes a manga bad. Though if I had to choose one it would be Lackluster plot.

If a manga has been axed or rushed the author should at least make the effort to make the ending good, for those that enjoyed the manga. Kagami no Kuni no Harisaguwa perfect example of a bad/weak ending.
Lame main characters are mainly in Harems and fan-service type manga which I don't enjoy at all, so I don't read them. If a manga I read turns into a Harem or goes for random fan-service I tend to drop it. I don't really understand why people really enjoy these types of manga but I guess that's what the majority enjoy.
If a manga has lackluster plot it basically, to me, ain't worth reading. Especially if the plot takes forever to develop.

To me is "Bad/weak endings" because if they just have any of the other things... I just don't read them.

But when you've invested time following a series that's actually pretty good and then you get a lame ass ending, that just pisses me off, and unfortunately weak endings are way too common.

Lack of originality for sure. It's like most manga series are just recycled cliches taken from other series.
My inability to relate to any series is expected, especially romances (which is what I mostly read). It takes the character so long to relay how they feel. I dunno though. It's like the Japanese have a whole different set of problems than I do and that reflects in their works. Like I said before, getting a/the girl has never really been a problem for me. Never been bullied (actually was a bully when I was young). And I don't care about keeping promises I made when I was an adolescent The only thing I can think of that's similar off hand is that I don't have many friends (mostly because I screwed their girlfriends...). Can anyone really relate to a series (aside from getting the girl which plagues almost everyone)?

I can agree with most of them, but in the end even a story with great characters and an amazing plot can be completely ruined if the ending sucks. So my vote has to be "Bad/weak endings".

1. I haven't found a good story that I can't relate to. There is some shoujo stuff that I think is a little unbelievable so maybe I can't relate to that, but I drop it before putting any significant investment into it.
2. A good story doesn't always have to be "original". It can sometimes just be told really well with interesting characters.
3. Bad drawings can be a turn off for me, but it won't by itself sink a series if the story is really interesting.
4. I haven't found anything that is so complicated that I can't follow. Now I've encountered bad translations that are hard to follow, but that's something else.
5. "Lackluster plot". There are many stories with lousy or weak plots and its a problem in general, but I usually drop those early so its not something that ticks me off as much as the last 2 things:

Weak endings and lame main characters really rub me wrong. I really hate it when a series is rushed at the end and many things are left unfinished because the manga has been axed. I also hate when you have a decent story or its got some cool elements and you have a lame main character. I really get sick and tired of reading the phrase "must save everyone!" or similar trite junk. I also can't stand it when the main character has amnesia and can't remember someone from his past (memory loss must be an epidemic in Japan). Bland and weak male lead who has a ton of gorgeous girls mooning over him because what he's polite? Please! I guess lame characters irritate me more than weak endings, so I voted for that.

Endings.
Endings can either break or make the series.

Whether or not I can relate to a series usually has to do with the characters, so that's what I voted for. Good characterization can make up for a lot of things - as long as I care about the characters, the rest doesn't matter too much, although a good ending is of course also important.

Something else that really bothers me is when the balance between humour and drama is off, or when the drama is treated weirdly/ the pacing is wrong. That's something that happens a lot in shonen ai/yaoi manga, when there is a ~dramatic revelation~ like that the main character's been raped when e was younger or whatnot, and it's all dealt with in two panels, and sometimes there's even a funny moment on the same page. That just makes it impossible for me to care about whatever happened to the character.

Definitely bad endings.

The other 'bad parts' -- when they're really too much of a annoyance -- make me drop the manga. But bad endings are unforeseeable. They're the real plague... -_-

I didn't choose an answer because for me the most annoying thing might simply be the slowness or incompleteness of the release. If I read a manga straight through, I may love it, but if I read it in dribs and drabs over the course of, literally, years, I might hate it. I don't know why that is.

Annoying main characters that make you want to hit your head against the next wall.

All of them, really, but I voted lack of originality since it can encompass a lot. I frequently drop manga before the end of the first chapter simply because the premise is overdone, the execution is poor, and/or the author didn't bring anything new to the plot or used unaltered archetypes for their characters. Reused plots and unoriginal characters have become extremely boring for me, and I find that the shounen and shoujo demographics fall into these molds more often than other genres. (It's probably because of their younger target audiences that authors and publishers think they can get away with this.)

Endings are a major deal-breaker. An overall average story can leave fonder memories with an excellent ending whereas an excellent story with a lousy ending is extremely disappointing and casts a negative light over the parts of the story that were actually good. For example, Full Moon wo Sagashite was an okay read, definitely Tanemura's best work, but the warm ending (despite it's slight dosage of deus ex machina) felt genuine and was quite welcome after bearing with all of the characters and their suffering throughout the series. On the other hand, Akusaga had a huge amount of inertia for a multi-volume plot as well as an excellent villain-protagonist with a lot of room for character development, but at only two volumes, the sudden and rather shallow ending made me feel like the manga's potential was cut off at its prime, leaving me disappointed.

As for being so complicated that it's hard to follow, I feel like this can be subjective based on intelligence and attention span. I love a good, complex manga with three-dimensional characters who drive the plot and are subsequently influenced by it, but series that are ridiculously convoluted to the point where plotholes are more common that potholes after the winter freeze frustrate me to the point of being unable to continue reading. For example, Vampire Knight threw me with its increasingly weird revelations and its growing number of contradictions and inconsistencies, and I dropped it while feeling very confused. Conversely, Pandora Hearts, while initially mildly difficult to try and piece together the overarching plot, continues to introduce new twists that, when regarded in retrospect, tie in perfectly with events that have previously happened, allowing the plot to be tight and consistent as well as pleasingly thought-provoking and psychological.

Bad art is also rather subjective, but I find that if the art is sub-par but the story is well-done, I can thoroughly enjoy a series. Natsume Yuujinchou has sketchy, fairly simple artwork that would be a huge turnoff if the story and characters weren't so engaging and developed. I've actually come to enjoy the artwork for what it is because of the excellent story.

Can't relate to the series is a big determining factor in whether or not I can keep reading a series. If I can't relate to the characters or the situation and I can't form any sort of connection, then I don't see the point in reading. Death Note is my biggest example of this. The story requires the reader to root for one of two characters, Light or L, but neither of them appealed to me because neither was genuinely sympathetic, and both of them were too two-dimensional to feel like authentic human beings, even insane ones. Their mutual sociopathy and their lack of humanity muddled an otherwise sound premise.

TL;DR: All these factors contribute to a very boring manga, but I think lack of originality is the biggest killer for me!

Bad/Weak ending is what 'plagues' me the most because of the things I encounter most often that is the one that bothers me the most. Lackluster plot I encounter less often, but that would make me not read a manga usually..

Bad / weak endings
In all the other cases I can drop the manga but unless I read spoilers I'm probably not aware of that a promising manga actually have a weak ending.

I've read a lot of manga out there, and I can only think of a handful of them that actually ended well. They were usually one or two volumes long. Anything longer than that seems to be axed by the publishers or given some completely ambiguous ending.

"....and the journey continues..." Yeah, that was the whole point of the story. You're telling me that we won't see the end of that journey now?! So, I've wasted hours of my life reading a story that will never truly end?!

Here are my choices: (Too bad I can only choose one on the poll )

- Can't relate to the series
(There are few series that I consider that "I can relate to this". Most of the Shounen manga has that problem, until now)

- Uninspiring / lame main characters
(In Shoujo, I hate it when girls portray there as one-sided, pathetic, and worse, martyr lovers >_>. But don't compare it to Kimi Ni Todoke!)

- Lackluster plot
(I usually drop a series when it sense that the plot is too pointless and weak)


I don't have problems with endings, character design, lack of originality, or its-harder-to-follow storyline.

Bad endings I can deal with but I'd say all the above. However, I picked Uninspiring/lame main characters.