It's not that complaining is inherently bad, it's that it tends to be uninteresting and unstimulating.

Yes, I know the sky is rainy grey today. It does nothing for either of us if you point that out for the fifteenth time. On the other hand, if you compare the sky to a giant peeing elephant, then we're now engaged intellectually at least a little bit.

Personally, I don't complain unless I can come up with an interesting way to spin my complaint.