The mother of the main character (MC), acted like a really money hungry woman at the start. She seemed like she didn't really care about his family and son. The MC though, looks up to his mother for bringing him up. The MC was also noted to have been brought up by a good person according to others. At the end, she seemed like a dignified person, even if she was portrayed to have been selling herself at the start.
The MC was also out of sync with himself or ideal morality, taking kisses from men like it wasn't a big deal, and talking to his girlfriend in a straight face saying he had sex with a man. Also, like on chapter 22, his girlfriend notes that they weren't having sex anymore showing how experienced the MC is in the act. In some scenes though, the MC acts like a virgin and is so against about the idea of it (he shows disgust on the adultery of his male love interest - while he was doing the very same thing).
Even the timing of how things jive is quite poor in this manga. Its like they are living in a very small world. For example in chapter 23, the MC said he wouldn't be gone long, but instead, even had the time to have sex without a care for his promises. They just ran about and seem to be finding people right on time.
When the MC hears that his other love interest was going abroad, he rushes to his side like he's an innocent partner and even makes out again with him at the end.
The MC also barely even went to class in the whole series. His relationship with the girlfriend never even got sorted out. She was portrayed as an idiot who only loves sex.
This also shows how low the main character's values were, even though he was described as a good son and good friend by everyone.