I've been meaning to post this story for ages...
Many years ago, I was a server at a popular chain restaurant. I'd just transferred from a location near my parents' home to one near school, and ended up starting at the new store on my birthday.
Toward that end of my first shift, I mentioned to another server that I was glad we were on the "early closing" side of the restaurant, because I had friends coming over to celebrate later.
Not five minutes later, I had a swarm of my fellow servers singing Happy Birthday to me in the middle of my section.

That was sweet, but not even the nicest part of the story!
One of my last customers was saddened that I had to work on my birthday. I explained that I'd felt silly asking to start on a later date, but it was ok as I was getting out early anyway. We chatted a bit more about how the new school year was starting up, and I was away from home. She mentioned that her son had also just left for school.
Before she left, she came up to me, gave me a hug and pushed a $20 bill into my hand. She said that it was a birthday gift, not a tip (and there was actually a separate tip on the table!) and she wanted me to have a little fun on her, "since my mom wasn't in the area to spoil me herself."
I've never forgotten that amazing kindness from someone I'd never met before. I hope to be just like her when I grow up!