About a month ago, one of the department heads at the library had offered some criticism while we were working a shift together, mainly that I was too timid. One of her specific concerns was how I would handle a difficult patron.
So, I was pleasantly surprised before a recent shift that she spontaneously retracted her criticism and complimented my performance instead. That was a very gratifying feeling. She followed this up by telling me of and printing out for me an ad for a more stable and presumably better-paying job elsewhere and offering her assistance in case I need help brushing up on any areas of library work I don't interact with in my current position, such as cataloguing.
I had to make an effort not to be a bit floaty-giggly throughout my shift. Very, very gratifying.