Evade, Run, Cover, and Action being the same button: sometimes you want to evade, run, or cover from enemies... But character activates device or tries to revive a teammate(not abandoning a fallen teammates, I just cant save him/her if I die too) and dieee :=
Not being able to start running in 3 other directions other than front.
Game Loading into an already started match, Im not even there yet and Im already under fire!!! >

Random ultra rare weapon low drop rate system.
Not having a mute funtion. Some people are annoying.
Those people who say "Oh no, we need a vorcha/geth jugger to have a chance in gold/plat". Bixch please -.-
Activating devices on 8-10 rounds, on open locations with few cover and long range enemies. Drawing enemies attention and taking them for a walk away from mates activating devices or recovering object... Then some idiot launches a missile and all of them respawn close to the guy in work U.U
Flamers with LOW teamwork behavior that throw themselves into the middle of the enemies in the open.
Those hosts that quit when game gets harder and made others to waste their items.
Being on round 11. Hosts quits or leaves. The rest succesfuly get and the spot in time

and times runs out. "Yeeeeeeessssss we did it!!!!!" ... MISSION FAILED... ¿¡WHAT DA FAQ!?! WHY BIOWARE!!!! WHYYYYY UUUUU >