It is annoying, but here's my top list of annoyances 1. Teammates that can't be bothered to run around you. 99% of players seem like they have a quota on how many times they can bump into, or ram into you, especially in the middle of a firefight, or when you're trying to back peddle away from a shotgunner/glaiver, or trying to grab heavy/special ammo and knock you away. 2. Titans that throw a barrier up right in front of a doorway/hallway, when you're in the middle of a firefight, and the enemy you're shooting only needed one more hit to die. 3. Teammates that have a keen sense of being able to run/jump right in from of you, just as you throw a grenade/smoke bomb. 4. Teammates that will watch you knock an opponents health down and then only fire when the opponent is one-shot-able, to steal your kill. 5. The "You have to use the play style that I want you to use" teammates, that will sit and shoot at you if they see you crouching and shooting enemies from afar.