Seriously...

Why does one troll a game?

Like honest to god, why?

BTW the answer to your question, imagine that you go out to play basketball with your friends, one guy comes to you, takes your ball, and wont give it back for 20 minutes, and you are not even allowed to leave. In this case wouldn't you get angry at the guy? This is the same with trolls in LoL, you are basically held as hostage in a game, where you have no fun (who likes to be oneshotted?), yet you can not leave, bc YOU will be punished.

When I tilt it is because I am trapped in a game with allies who refuse to work as a team. I HATE feeling like I am being held hostage. I've afk'd in more games this season (across my multiple accts) than I have in every previous season I've played combined. I have no problem losing, I have no problem having unskilled allies, but I absolutely tilt when my jungler afk farms because he got counter ganked bot and now he hates everyone on the team.