Most of the time whenever I see an assassin player in the game they are so extremely rude. Most usually mid lane assassins like Talon, Fizz and Zed should roam and impact other lanes when they are like 2 kills on their opponent, the reason to stay in lane at that point is just dragging uneccessary jungle attention which could be used elsewhere. But if you ask someone who doesn't roam even after the 4th kill against their laner, "Hey, mid can you roam bot?" They always respond "DUDE, NO WIN LANES BY YOURSELF LITTLE LOSER" or something like that.
Same goes for assassin junglers, assassin junglers like Kha, Rengar and Evelynn usually never gank anyone, but just constantly invade the enemy jungle even if it's a stupid idea. Then if they die the the enemy jungler and a enemy laner, they always flame the lane where that laner came from, like it's their fault he didn't respect the enemy's faster ability to roam.
Barely never is it a fighter (execpt Jax players) or a tank who does this, it's always the assassin players being super rude.
And I can make an entire post on how Yi is the most toxic champion in LoL... But I think that reward goes mostly to Riven, since she is the most reported/player banned champion in the game.