At least once a year around this time, I get a table that pays with a gift card - doesn't take a cent out of their wallet for the lovely meal and service I have provided them with. Seriously, this bitch is bubbly as hell and I try and make you happy, I do.
And THEN, the douchebags don't take a cent out of their wallet for a tip. I will remember you, middle-aged couple. I will remember your faces, and I will be cold to you next time you come in.
A very stark contrast, two weeks ago I had a deuce who did it RIGHT. A table in my station slipped me a twenty and said, "please put that toward that couple's bill, try and wait until we leave."
So I did. As I dropped the check, I pulled out the twenty and told them someone wanted to pay for some of their meal. They were flattered and excited, and tipped me a ten on a not-quite-thirty-dollar tab. It was a pleasant surprise for this jaded little waitress.