When I order something for delivery, I tip the delivery person for delivering my food. No one else gets any tip. So if I get takeout, then I shouldn't tip, right? After all, there's no delivery. So how come I feel guilty when I don't tip, especially when I pay by credit card and I leave the tip line blank? It all got a bit ridiculous when I went to one restaurant a couple of days ago and sat at the bar while waiting for my food to arrive; I tipped the bartender for my drink, but tipped nothing for my food. Was that OK? And what should I have done if the food and the drink were on the same tab?

Tipping, as we understand it, is a function of service, not food. That is why waiters get tips and cooks get compliments. If someone actually served you an entire meal, you should have tipped him based on the total charges for your drink and food. A restaurant might bill you on one tab for convenience - one slip of paper, one credit card swipe, etc. - but since you were only biding your time at the bar before your food was brought from the kitchen in a plastic bag, you were right to only tip the barkeep for the drink.

You are under no obligation to tip for service when there is none. However, in establishments where a tip jar can be found at the the counter your guilt might persuade you to toss some change in before you make off with your lo mein or chicken fingers.

Related: Ask Gothamist on tipping delivery people.