In college, my friends were throwing a party. $3 got you a cup and all you could drink. It got out that I didn't pay for a cup. I thought I "earned" it by being friends with the hosts. I was berated by a unknown senior for not paying my friends a measly $3, if not more. "How could I so cheap?" he asked. It was an early lesson in karma and it changed the way I live.
From that day forward, I took the scolding to heart. Ever since, I've never thought that I deserved something because I was a friend of the host, or something was in my town. I pay because the occasion requires it. I tip more because someone just brought me food that I told them to do. And they do it with a smile, no matter how I treated them. I pay because when I do something good to someone else, good will happen to me.