Hit Box Clarity
Blitz's grab, Thresh's Hook, Lux's Binding, etc. etc.
A lot of the time when I'm playing a game, I get hit by one of these spells, when I feel like I shouldn't have. When that happens I immediately thinks its a glitch or bug. After some time passes and I come to my senses I know that the hitboxes are not the same size as the character models or abilities. I accept it and move on.
Objectively looking back on it I don't really see a need for hitboxes to be so "undefined".
I think hitboxes need to be scaled properly to the character models and abilities or some sort of outline needs to be shown so that there can be no doubt as to whether or not you were hit by the ability.