I admit it. I was one. I have seen the light.
Often when you're a well-intentioned employee, you want your company to improve its barbaric ways. You don't stop at IdentifyTheWorstProblem, you make sure everyone knows about it so that we can get off our butts and do something about it. You're not exactly sure how to solve the problems, but we need to do something (AnyXisBetterThanNone, right?). When the boss starts babbling about what he thinks the major problems are, you let him know, in no uncertain terms, how wrong he is.
But you never seem to be able to motivate anyone to do anything...
Therefore,
Realize that nobody likes a complainer. Nobody helps a complainer. A complainer may have the most amazing idea in the world, and nobody will listen. Why should they? The complainer doesn't listen to them, after all. Convincing people is not about logic, it's about understanding. Nobody will bother to understand you unless you take the time to understand them first (see SeekFirstToUnderstand).
Learn as much as you can about social skills and influence. Read books like HowToWinFriendsAndInfluencePeople. Above all, StopComplaining!!!
It is easy for other people to recognize a ChronicComplainer, but the complainers don't recognize themselves as such. If the following statements seem true to you, then it's possible that you are a ChronicComplainer without realizing it:
I wish someone had told me this 15 years ago.
Let me suggest a more positive way to say "Above all, StopComplaining!!!": FixBrokenWindows.
Most of the time, the same force that generates a complaint also generates an opportunity. Instead of complaining "The fribitz is broken again", try saying "Here is a gabille that seems to work better than the fribitz". As it becomes a habit, you may find that both you and your companions enjoy your company more.
For more on turning complaints into positive action, see ActInsteadOfComplain, LeadByExample.
I've tried this myself, and in my case it definitely worked. Instead of complaining, I would take the initiative to help the people I was working with to solve their current problems, one at a time. This builds respect and trust, allowing you to eventually guide the changes you want (many of them anyway), without the frustration that ChronicComplainers get.