Echoing the above sentiments, I have to hand it to so many awesome DL F/As I've had. I flew JFK-KEF back in June and upgraded my mom along with me to F - and my mom is the 2-3x a year flying type, and she never flies F. The F/A (I think her name was Zaffrea) treated her like she was a queen - my mom was thrilled.

I handed the F/A a JWD certificate on my way to the lavatory, and when I came out, she was standing there and asked me to give her a hug because she was so happy.

I think that DL's F/As are some of their best assets - of course, there are ones who aren't bringing their A-game to the table, but by and large, I'm consistently impressed with how friendly and service-oriented they are.