On another forum, we had a concept of "candy for the crew week". I'd like to offer an additional suggestion. On your next flight, or every flight from now on, pay attention to something that the crew does very well and compliment him/her/them for it. Maybe you already do this. Cool! Keep on doing it. Personally, I tend to thank the SD at the end of each flight for the great service (assuming the service was great, which it usually is). I'm going to make a point of complimenting other members of the crew for their service. Maybe they were really friendly. Maybe they went above and beyond. Maybe they did something amazing. I think that if AC staff feel appreciated by their customers, it can only foster better service in the future.