In the case of takeout or counter service, I may leave $2 or some such, for the effort of packaging, I guess. All they do it hand me a bag that I carry home and place on my table. Takeout is pretty much limited to Chinese for us. I think I've maybe dined inside a Chinese joint 5 times in my life. If that.
I did one time order delivery for Subway, and it asks for how much you'd like to tip your "sandwich artist". WTF is that?
Pizza delivery drivers.. I'll tip a bit, maybe $5 or something.
We don't do a lot of food delivery.