A question of etiquette

Interesting thing this waiting until everyone has been served until eating bit that we’ve all adopted. I admit that munching down on chicken leg when no one else has anything else to eat is probably a bit on the rude side. But, when you’re all sitting down to sup and all but one person’s meal has come, why do we all wait? Most foods don’t get better when they get cold and I guess it’s the socialist in me, but it just doesn’t make sense to have everyone else wait. I don’t care if everyone starts eating when I haven’t been served and I’ll take advantage of the situation if the reverse is true.
Of course, when you’re eating in an intimate setting, with just two of you, that’s something quite different. There was this one time though, when myself and a group of co-workers (15 in total) were out having a lunch at a cafeteria-style place and we did the waiting bit. Myself and another miscreant said forget it, we have spaghetti in an alfredo sauce, we’re eating now.
Most of the time, the waiting feels forced anyways and seems to be adopted by those who want to seem like they’re very sophisticated, since I see them, as they’re talking after their food has been set down, trying not to eye it, looking around to see when they can start, wanting to start, dying to start.
We’re a silly group here in the States.