Most complaints are crazy to begin with because they are about things the person recieving the complaint is not responsable for and cant do anything about. Corporate via customer relations should really be getting the earful (and even that should be done in a correct way if you want any success.) FAs, GA's, etc etc are normally not to blame for travel related issues but everyone pees on them, which is crazy because they can do ALOT to make ones travel experience ALOT better or ALOT worse.
My philosophy has always been to be as nice as possible to them and also any other "gate keeping" staff wherever they may be such as secretarial staff, PAs etc etc. You'd be surprised how much they can help one out if they like you.
My philosophy