Short backstory: I have been doing parking duty(I am essentially a crossing guard) for a few weeks now and see the same parents everyday. I wave at every car that comes by and say hi to all the parents who come through.

Today, this one Dad comes up to me and introduces himself and essentially thanks me for being there. He said something along the lines of, "I always get excited to see you all in your positions and having a big smile on your face". It was awesome and made my day. I had a short conversation with him, and he told me his name and thanked me for giving them a good camp experience. As he said that he gave me a good handshake. This made my day. I don't get paid much at camp, but the lack of pay is made up with seeing excitement on peoples faces. And seeing the excitement on his face made me extremely happy. This was probably one of the best complements I have ever received.

tl;dr: Parent at a daycamp I work at made my day by just saying thank you.