So, this has happened to me a few times, when the customer orders by credit card, they say they intend to tip, but don't have any cash.

Now i can understand some people not knowing that they can leave a tip on the credit card slip, and I point it out and let them know that they are able to do that.

But it flat out urks me when they say they intend to tip if they had cash, are given the option to tip by credit card, and they give you that awkward "oh shit" look, cus they know they weren't really serious about wanting to tip, it was just a false front so as to save face the fact that they had no intention of tipping in the first place.