Custom 2v2s, aggression and micro

Well, I got completely stomped today in a few 2v2s.  I am going to have to work on reining in my aggression, and doing better on my micro.  I hit 2v2 platinum with one of my 4 teammates (although he's Diamond, so I guess I'm just being carried), and at this level, you can win or lose small fights with good micro.

For example, did you know that it's possible for 4 Zerglings to beat 4 Zerglings with 3 Zerglings left over, if you micro yours and the opponent doesn't?  I still have to learn the trick, but it involves moving your almost-dead Zergling away for a second, and then coming back to gang up on another Zergling.  It's a version of focus-fire, but you can't target just one Zergling with all 4 of yours, or you'll spend too much time moving and not enough time attacking.  It's very tough to do.

Aggression is normally good in 2v2.  However, what I have to learn is NOT to throw units away doing it.  It's often not worth it, either because either:

1. You force your opponent to go all-in, and after losing your harassment units, he'll have more army than you and roll you over, or
2. You don't actually do as much damage with your harassment as it cost you to make the units!

These 2 points are why Mutalisks are so good for Zerg - they are fast, their damage is quite high, they fly, and can easily escape.  Banshees are similar because they can cloak.  Blue Flame Hellions with a Medivac are also effective, because you can load up and fly away.  Protoss have their Dark Templar, but often those end up being throw-away units, or a sucker-punch that you hope will end the game.

And remember: if you're getting stomped, sometimes it's just better to stop playing for awhile rather than lose, lose and lose some more.  Go play the AI a bit, and you may figure out what the problem is.