Probably can find a more memorable one if I think longer, but off the top of my head a recent case where I intently tip gladly as a matter of principle is at Starbucks (of all places)

Reason: service is always great, they ask how you're doing etc. it's nothing exceptional or mind-blowing, just that the bar is so low around here (cough Tim Hortons cough) that it's a breath of fresh air.

For the US folks: imagine getting your coffee or burger at the DMV for years then eventually going to Chick Fil A for the first time