Funny story about tipping:
Once when I was 10-13 years old, my dad ordered pizza for us. As usual, my dad had already worked a 12 hour day and he was beat, so my big bro and I went outside to pay and get the pizza. Usually, my dad gave us money to give the delivery guy a tip. On this particular day, I guess he was too tired and didn't really notice how much he gave us. I think there might have been less than a dollar for tip. Anyway, my brother and I went outside the apt building. I got the pizzas, my brother paid. As we were walking away, I heard the guy muttering, "I hate my life." My older brother wasn't paying attention, and replied, "your welcome."
Poor delivery guy! He was probably having a horrible day, and a 13 year old kid added insult to injury. I tease my brother about it to this day.