So, when I first read this oneshot, it made me terribly sad. I came up with the same theory as Meilee and thought that the story wasn't realistic. I mean, anyone would quit their job if they were mistreated to that extent, right?
However, I was going through my posts on facebook one day and a person explained the whole scenario of suicides/overwork in Japan really nicely. Sadly, I can't find the comment but I will just try to write down what I remember.
So basically, in Japan, when you enter a company, you are labelled as 'capable' or 'incapable' within a short period of time and that is what decides your reputation for the years to come. Japanese people don't usually change their job because the company is like a family to them. The company, on the other hand, hires you with hopes of long term investment. If, say, an employee switches their job, they are usually looked down upon in their new workplace. They are perceived as unfaithful and unreliable because they can quit their new company just like they did with the last one, and no one cares about the reason. There are a lot of other factors and you can google that if you are interested. But either way, the life of a normal office worker in Japan is pretty difficult.
Now about the story, this oneshot was a really sad read for me. It shows the painful transition from the innocent life to the adult life. Despite being madly in love once, a person can change depending on the time and situation. Though, there are ways to prevent that, but the characters here decide otherwise. Even though I am sad, I am also happy that both the characters managed to find a more suitable partner for themselves and that they both have stories of their own.