I think a lot depends on context. There are certain situations where complaining can be a way of being social - shared annoyances and all that. And sometimes it helps to express the things that piss you off so you can get over it. As elainetyger says, an awareness that you're complaining helps, too, as does doing it in an entertaining manner.

But some people seem to only dwell on the negative, seem to never be happy, or worse, are only happy if they're finding fault with something or someone. Those people drive me nuts. I either feel like they expect me to do something about it and I can't, or I start to feel resentful about the same things and I don't really like feeling like that. I do think that there's something to the "choose your attitude" idea. Not that it's a panacea or a way to fix everything that's wrong, but it makes the day-to-day stuff more pleasant.