I have a funny anecdote about Tipping...
My sister and I were the only 2 people who were home, and I had to go to the bathroom. As I'm walking to the bathroom, the door bell rings, and at this point, I was doing a Pee-pee dance. I told my 12 year old sister to go pay the guy, and handed her 20 bucks. She walks back, after I finished in the bathroom, and hands me like 4 dollars. So I asked how much it was and she was like, "Well, it came to 15.50, and I thought 50 cents would be enough"...
I still tease her about it to this day.