My mother and I were waiting for my dad to pull the car around after our meal at a restaurant when I noticed a group of very cold people hustling to the the door. I opened the door for them so they were able to get out of the cold a little faster. One of the gentlemen said "wow what service! I hope they pay you well!" And I replied "no not at all, but I do take tip." We laughed and he went on his way. Shortly after, the same man came back with a folded bill in hand saying he had a tip for me. We were shocked and my mother insisted that I couldn't take the mans money. He slipped the bill in my pocket and ran back to his party. Not wanting to be rude I didn't check to see the amount till I had gotten to the car. To my utter shock it was a $50. I had figured it wouldn't be more than $10. We were all pretty excited about it. That was several years ago. I still open doors for everyone; not because I expect anything in return, but because it's the right thing to do.