I learned the goodwill of bringing a box of candy (from posts on flyertalk) to the flight attendants when I fly internationally. I give it to a flight attendant working in the E+ area where I sit usually after the first round of drinks. Since I try and get exit row seating, I used to give it to the flight attendants sitting facing me in the exit row. Usually they are business class flight attendants so I wouldn't see them until we landed. So now the candy goes to the flight attendants in my area. They always share it with their fellow workers and a stream of them come and thank me throughout the flight. The smiles and pats on the arm say it all. It's nice to be appreciated.