For me it's the people who are all happy and spam their taunts because they are stomping a match becuase the team you're on sucks, but then rage and get astronomically salty if they lose or get stomped, and ragequit saying "report my team for sucking".
What are your hates?
If you call a champion a hero.
Go back to DotA you mofo.
Basically everyone in league. Too much toxicity to find the good people
Anyone that says "gg ez" when 
isn't in game gets an auto report.
About 60% of everyone I play with. ( I play support )
People who act like they're good for playing some fucking broken champ like LB, Kat, Jax, Yi, Xin or any other braindead clicker who, for some reason, instantly deletes anyone they come close to.
and 
players
When trying to be social and/or communicate with the team and NOBODY puts anything in chat. So then I start talking to the other team...
People who refuse to play support
The players that type too much and are a overly optimistic while they performing very poorly.
everyone. there is barely any kind of player i really want on my team only the guys who is always calm and likes to joke
people who surrender a competitive game no matter how casual you are the object of the game is to compete
The jungler that camps top helping a feeder, when i'm clearly winning my lane and we can snowball.
My hates are this:
[ALL] randomdude69 (Teemo): HAHAHA [ALL] randomdude69 (Teemo): LOL [ALL] randomdude69 (Teemo): LMAO [ALL] randomdude69 (Teemo): TEEMO OP HAHA [ALL] randomdude69 (Teemo): NOOBS [ALL] randomdude69 (Teemo): 2 EZ
The one guy on the opposing team that insists on blowing up chat every time he gets a kill. Nobody ever replies, yet he still just keeps talking.
:^)
^ This shit right here. Spam that after a kill and become the tilt god.
The cry babies
