Since I've become a Chowhound and read postings from food servers, I make it a point at all full service restaurants to tip at least 20% unless food and/or service are well below par. For my area, that is a big tip, but I like to reward service, and waitstaff locally make $2.13 an hour without tips. But my question concerns what to tip (if at all) at those other types of places--buffets, or places where you stand in line to order and then pick up your own food, or spots where you stand in line and order, but they bring you your food. I feel silly tipping 20% for minimal service, yet these are the very restaurant workers who are lowest on the totem pole. Should I tip less or not at all? What do the rest of you do?