I think it already occured to most of you: Sometimes, I have really good games, lasting for "about an hour", where I have the impression, that all the players enjoy the game - WHICH IS THE F... ONLY REASON WHY ANYONE SHOULD PLAY IT, BLOODY HELL! - and that all is fine, altough there are players of very different skills, however, all is fine, and I really endulge myself, which can be wonderful after a hard day's work (especially before Christmas, when all the customers go mad, btw.)
Then, I play matches that really
ssssuck. You've got some elite players, some unskilled players, some noobs and newbies, but nothing is right, it is all a mess, the game lasts for about "five seconds", no matter if (as usual) aliens win, or if humans do.
And one time, I started to realize why.
It's definetely not the skills. Really! Because in both cases you've got teams of mixed skills et cetera et cetera, so what is it? Two words: Cooperation and balance. And, as a third (did anybody expect the Spanish Inquisition

), IQs that do not go below 60... end of rant. It is because players have a minimum of respect for the others (including the opponent team) and are not too dumb to count 1+1 together. But I am babbling, let's summarize:
In a good (human) team, people have realized, that you are nothing agains a dragoon if alone, that it is a good idea not to waste money for the even bigger gun. People tell you what they are planning to do giving you the chance to cooperate with them.
And if they realize, that one team is way too good, they switch, making the game balanced again, just to give everybody despite his skill the chance for a long, joyful game. In the end, the skilled can say, "Bad day, I only killed 34 609 noobs this game" and the unskilled are happy because they got enough money to get a luci-gun for the first time in their life, and even survived long enough to try it out. Everybody's happy. Perfect.
Now, to the b-a-d team: People are running around like frightened chickens. Got 500 credits? Go buy the biggest gun! Well, they get killed instantly because without a helmet, they don't see those dretches that have been walking right behind them for a minute, but hey, the got BIG guns...

No joke, I have watched those people. And if someones a far better player than others, why should people care? Why should those players try to get to both teams, if they are in a slaughter-raid? It is about yourself having fun, who cares about anybody else in the game? Also, people always go alone. Just always. Because it is about YOU making money, who cares about that this is team game? Okay, you may have been feeding the aliens for 12 times, but now you have a few bucks to get this really biggg gun.. The base needs no protection because it surely has those turrets and can defend itself, so a builder is not necessary as well.
Über-nerds of this world, I have bad news for you: You mave have fast reaction times or slow reaction times, you may have learned all the maps by heart or have no idea of them, it all doesn't matter as long as you are lacking one thing, that is essential to any team game: social skills.