101 Reykjavik by Hallgrímur Helgason (1996)
Hlynur is 30+, unemployed and lives at his mother. His daily routine is something like this: wake up late, drink too much coca cola, eat cheerios, smoke, watch porn, go out, stumble home or elsewhere drunk and repeat. But when Lolla, his mother friend and worse, rumoured girlfriend, moves in, Hlynur is forced out of his comfort zone.
I don't think I have ever hated someone in a book as much as I hate Hlynur. He seemed like the worst pathetic guy you could come across. He was okay in the beginning of the book and then he just turned into a prick. And I actually threw the book into the wall a couple of times but had to pick it up and continue hoping that he would die a terrible death at the end, hopefully by his own hands. I was really disappointed when he was still alive at the end. I also started skimming a lot midway because I couldn't deal with his thoughts. I sincerely hope that the author meant for him to come across as the biggest jerk.
It's funny that the main character can ruin a book so much. Because I loved the rest of the characters and the setting, but not Hlynur. And when the book is about him, I just can't like it.
If you're curious what Hlynur did, you have to read it yourself and judge because I don't think I can get into it without raging. And yes! It's amazing that I can feel this way about a stupid character in a book.