Most of the domestic DL crew are pretty good humoured in my experience.
Last year when I got a first upgrade, I ordered two bloody mary's during the flight. Apparently the guy attending first thought I was on a nice binge and quietly made me another.
I tried to refuse, got a way overdramatic and VERY sad puppy-dog eyed face with a 'But I made it especially for you' comment. Annnd, there goes
#3 down the hatch. Couldn't refuse after that.