My work schedule makes it difficult to get a haircut. I have to specifically plan ahead and go to a walk in welcome type of place. So, I did that on Sat. She was great, talked, but not too much, no lame jokes, laughed at my one joke about my 'cowlicks' making me look like an cartoon character. I get a bill for $32, pay her $35 and go about my business. I get home and realize I forgot the rest of her tip. She got a$2 tip. They typically have to do a lot to trim my hair down. My standard joke is to look at the floor and say. "Looks like a shitzu exploded."
I went back today, keep in mind I live and work in different towns. She was working today, the desk person called her over and I explained my error and gave her the $10. She was so happy, thanked me, blessed me, it made her day. (Well, only fair since I may have ruined her evening with that $2)

Kind of made my day too.