Eh I don't know. I spent many years working in food places, both traditional sit down restaurants and counter-style. I usually tip pretty well even at like ice cream spots, but even I am starting to get annoyed at the request to tip the assembly line crew at Moe's or if I'm just picking up a Papa Johns pizza. To me the difference is whether the person has any autonomy in what they are preparing. If the dude at the local deli loads me up with a fat roast beef sandwich bursting at the seams or the girl in the ice cream shop makes the cone so that it isn't going to topple over when my kid grabs it, I'm much more inclined to tip than the dude squirting 2.5 shots of sour cream into the burrito because that is what the corporate stooges 500 miles away stipulate for the recipe.