Some customers stand out for being nice - have you made an extra effort to help them out because of it?
One time at a convention, I was helping run my Mum’s jewellery stall, and a really lovely lady really wanted a necklace, but didn’t have quite enough cash - Mum doesn’t take cards.
With Mum’s approval, I paid for it for the (very surprised) lady. She nearly burst into tears, because it was a present for her Mum, who wasn’t very well - which I didn’t know.
That’s such a nice thing to do.