I know it sucks...I have been in a position like that countless times. Many times, when a person is screaming "NEED ONE MORE PERSON PLZ" I switch, only to have the team I was just on lose a player or two so the teams are no longer even. I get tired of it after a while, especially when a server is almost full and people are joining all the time. Not sure what we can do about balance of skill on a team though, besides practicing what we preach, but it's pretty sad.
I did see some really poor sportsmanship today from technogenius, superman, and others who complained and swore quite a bit. There was a lot of swearing today, and it is really contagious on a server...someone gets frustrated and swears and others think its ok.