I like when people compliment my smile, which happens often at work. I try and stay positive, and it does get noticed. The one that stands out the most, though, was a couple summers ago, I was ringing out a youngish black man. I was working like crazy, when I caught him out of the corner of my eye trying to make eye contact. When I looked up he said you have the same kind of eyes as I do, they're yellow.
I laughed, and said, they are normally green, but when I get excited or angry, they do turn yellow, where his were more on the amber side. I told him thanks, and that I did like the color of his as well.
I confirmed with a friend after he left that they were in fact yellow.
I also like when a customer remembers my name, even though I don't have my badge on.