Last night my friend Scott and I did an annual tradition of ours, something we have done for many years each holiday season. We pick a reasonably priced restaurant, nothing too crazy, and go out for dinner, and exchange birthday presents. (His is new year's eve! He's always going to be 13 days older than me. I get a little joy out of this.)
Anyhow, the christmasish (sure, it's a word) part of the tradition is that after dinner we leave a 100% tip in cash, and a nice note, and then quietly ghost on out of the restaurant, so the server doesn't have to be awkward about it.
I've known Scott for decades. We've done this a lot. It never, ever gets old.