Runescape - You will just get called a "Noob" every time you do something, extremely annoying.
World of Warcraft - I was in a guild and I fought with the leader/teammember because I had a higher GS than some of the player, my dps was not higher than them, then I think some players in that guild also harassed me ? One day I got a high level trinket because I rolled 100, then some player was also jealous of that, then the low things keep going on, so I got kicked in the end, I move on and went into a new guild
(laptop was kinda not designed for gaming, but still, it was just rude)
League of Legends - Yeah it was a absolutely a shit fest I don't even want to talk about it.
I can mentally handle all those things, those games are fun, but yeah I mean like any competitive games I played there is toxic player base.