The love interest in this is hideously emotionally abusive (true to the title, "self-centered", but in a horrible and most unlovely way) and seeing them hook up in the end did not make me happy at all.
The protagonist (who seems a pretty decent, considerate sort, who I would not wish harm upon) should have stuck with that last girlfriend, she seemed a little bland, but nice. Instead of an unbelievable prick with a heart made of sewage.
In short, I wish I'd never read this. I think this is for people who think being selfish is cute or hot or something, but I swear it feels more like a cautionary tale on when you really should just cut toxic people out of your life and move on.
What in the hell? It's not as if this story wasn't entertaining but I always hate when you're left with the feeling that the coupling at the end is a result of brainwashing or desperation or delusion... as if there wasn't any other choice left to make but to be with a very unlovable person. Tomo is a nice, considerate guy and Hideaki is a violent yandere. Just doesn't seem fair in the end.