I'm starting to hate Arenas almost as much as Quick Plays:
-Anytime I enter one, I either get booted immediately, or after the moment they see who I'm using. If it's an arena reserved for friends, lock the damn room.
-People don't know how to do proper team battles. If it isn't just a fun chaotic romp, it's vanilla rules with no team attack. Worst of both worlds right there.
-Speaking of team battles, I get people ganging up on me more often than not. It's fine every once in a while against inexperienced players, but most of it comes off as a passive-aggressive response. For this, I mean 3vs1 shenanigans, not 2 players teaming up in a 2v2 match. That's a different monster altogether.