Since you guys brought up the topic of team games:
One of the more annoying things is when you are teamed up with someone who won't assist you in any way.
As an example: you get a bad ore spot and they have the holy grail of ore spots, and they won't send any units to help defend your base while you optimize your meager metal production.
ALWAYS be ready to help your partner out in any situation. It doesn't matter if they are a weak player who will be destroyed no matter what, at least give them a chance to contribute.
Now, as to quitting, I have a question for your guys opinion:
I'll use a scenario that happened between Paco and myself back on WON (though, he doesn't remember it).
Players: 2
Map: La Corr
Let's face it, Paco has always been a top-notch player. A 1 v 1 against him left me with no chance in the first place, but I still played. He plowed through the computer base and decimated my meager army of lynxs. I knew I couldn't produce enough units in time, so I said "You win, gg" and detonated a supernova next to my own CC.
Would you guys consider this method of admitting defeat a valid one, or amungst the ranks of quitting before you're even attacked.