Great thread, BB!
I make it a habit to
1. be polite and friendly at all times
2. not hold the low-level person at fault. They don't run the airline in any event...
3. smile and make jokes, have good humor (we are all in this together anyway)
4. live and let live...not make a fuss if everything isn't quite right...respect others rights to be left alone as much as is possible in a narrow, claustrophobic tube
5. don't hesitate to make my needs known
I find that frequent travellers mostly do the same, I haven't yet found exceptions in fact.
The above is a bit selfish...I find my experiences in travel are so much better that way, and I believe it makes others' travels better too.
--richard