I too would not worry. I think the ONLY thing that complaining too much might do is reduce your chances at compensation. If you complain every flight that something is wrong with your seat, for example, you might not get much if any comp after the 3rd or 4th time in a row.

Totally beside the point, I do try to mix an equal amount of Rose letters (compliments for great crew service) with Onion letters (complaints). I do not feel this has any bearing on GS status, but it does have a bearing on people's careers so I want to be balanced.