There is obviously social pressure against pressing "No Tip". I feel it. But then I remember that a tip is for good customer service. Starbucks didn't provide

There is obviously social pressure against pressing "No Tip". I feel it. But then I remember that a tip is for good customer service. Starbucks didn't provide me any customer service, they simply transferred the coffee from their vat into my cup. At which point I can feel justified in declining. I guess they're taking advantage of people who aren't familiar with this view of tipping, which I'd argue is the standard view in the U.S.