Disclaimer 1: This probably breaks rule 5 but oh well.
Disclaimer 2: I'm by no means a good player, I'm pretty bang average and my stats are skewed by my braindead play when I first started playing in 2014.
But hot damn, I unironically believe the collective intelligence of the playerbase of this game is the lowest of any multiplayer game I've played in my 26 years on this planet. I've played plenty of FPS's, RTS's and enough MOBA's and none of them have ever left me as dumbfounded at the frequency of idiocy that is ever-present in this game.
Every single game there will be members of both teams that do such glaringly stupid fucking shit that it blows my mind. Whether it's top tier heavies or mediums red-lining, scouts yolo'ing, lightly armoured TD's brawling, lemming trains or some other hare-brained imbecile scheme, too many players on both sides make such dire decisions it damages the enjoyment of the game at mid and high tiers.
You could put this down to new players learning the game mechanics or the tanks they're in and this is forgivable, but whenever I check the accounts of players making stupid decisions I see scant few players below the 3k games played mark. Even unicums can't carry every single game, so how are average people like me supposed to make any progress when a coherent team occurs once in 10 games?