I never tip at places where I "take away" my food. The industry standard is not to tip people who make coffee and serve donuts, etc. I make an exception at bars where I tip in hopes the bartender will serve me before the endless throng of people waiting to order. And it is customary to do so. If I started tipping at Starbucks I might as well tip the high school kid at McDonalds making me my burger, the person who makes my sub and the Chinese take-out person.