I try to make it my policy to never recline the seat during daylight short haul (upto 3 hours) flights since I am a believer in "what goes around comes around". Despite travelling mostly in 1st class bulkheads on domestic AA flights I still don't recline since I wouldn't want anyone else to recline into my lap on a daytime flight. I just try to put myself in the situation of the person in the seat behind me and think how I would feel if it was me back there. Since the pitch is tight especially on MD-80's then it would be almost like pinning the person behind me to his/her seat which in turn will cause frustration and retaliation.

On long haul trans-oceanic flights I do recline but if not asleep I try to lift my seat if the person behind me gets up to go for a walk. In return I have noticed that I never get "kneed" in my back no matter how tall or large the traveller behind me might be.

During meals I prefer to sit upright not that it makes any difference since front cabin has in-armrest tray tables but I still believe it is polite to sit up rather than lay down while dining. It's probably more appetising for the person behind me to look at the back of my seat rather than enjoying the full view of my messy hair while having his/her meal.