Doesn't revive downed teammate
Steals teammates execution
That's annoying, too, but I don't think it's as damaging because this game is about stealth. Also, sometiems that's ND's fault. I've accidentally executed a guy next to my the teammate I'm trying to revive.
About 74% of all random players are **bleep** Steve.
Hence why I spend a ton of time in this game yelling at randoms to stop sprinting everywhere and that it exposes them on the mini map.