I ordered food for myself and a friend online and thought I hit the "tip X% with credit card" button. Because I didn't actually hit anything, the default went to "tip with cash". Another friend met me in the parking lot and she decided to wait with me while we chatted.
The delivery man showed up and when I said "thank you!" and reached for the food, he pulled it back and said "You're tipping me cash, right? It says tip with cash on here." He then proceeded to stare at me and wait with the food down by his side, and I said "I'm so sorry, I thought I hit a different button that tipped you online. I don't have any cash"-and my friend cut in and said "Oh, I have some cash on me." She turned to me and held out a wad of money (with some fives and twenties mixed in) and said "I don't know how much your bill was so I don't know how much you want the tip to b"-and the delivery man interjected and said "Oh, all of that's good. That whole handful right there." in a (somewhat) joking tone. The food remained at his side until I grudgingly peeled off a couple of dollars and handed them to him.
What I was going to say before my friend interrupted was that I would call the place, explain the situation, and try to tip him over the phone or online. By the time the transaction ended I wished I hadn't tipped him at all. When I called the restaurant to explain the situation (I wasn't happy at all with the driver) they said "He wasn't doing anything wrong asking you for a cash tip, you know." The whole encounter left me with a bad taste in my mouth. I can't tell if we were all in the wrong or what.