New trend: self-undertipping?

My wife and I ate out dinner tonight and an odd thing happened: the waitress tipped herself. That’s right. She filled out the credit card receipt herself. It’s just the two of us, mind you—we’re not a party of eight or more. And the weird thing is that she undertipped herself. The receipt was one of those that include recommended tips (telling you what 15% is, what 18% is, what 20% is, so you don’t have to do the calculations yourself), and she gave herself less than 15%. No, it wasn’t a round number. It was a completely mysterious tip.

The service wasn’t bad, actually. My wife and I were probably going to give her closer to 18%, but she chose to give herself 14%, so we just signed the receipt and gave her the self-induced under-tip. Weird. We’ve never experienced anything like that before.