I, for myself, thought, aggression means, how "powerful" the player tackles. Or respect decisions -> aggression causes cards.
But... I checked the attributes of my players, because, this season they got a lot of cards. I also try to find out, if they are just cosmetic or if they have an effect.
My player with one of the lowest aggression-skill got the most cards (without FA).
aggression 52% this season, 15 games, 4 cards (2.most cards: 3)
aggression ~69% 12. season, 42 games, 7 cards (2.most cards: 2)
aggression ~85% 11. season, 38 games, 5 cards (2.most cards: 3)
aggression ~100% 10.season, 46 games, 8 cards (2.most cards: 3)
The lowest has 22% aggression this season, but 3 cards.
Last season, he had ~40%, but got 0 cards.
I also aviod hard tackling, I usually use normal tackling - if fouls are too much, I switch to easy.
So, I don't think, aggression don't cause cards.
What are your thoughts about aggression, or about the attributes generally?