Honesty: Is it really important?

Am I an idiot? I had the chance tonight to make 10 dollars and cost a girl 10 dollars. I went out tonight for the first time in a few months and when I ordered my beer the barmaid give me change for a 20 even though I only give her a ten. Why should I have been honest and corrected her mistake? I was actually 5 or 10 foot from the bar when I noticed that it seemed to me that I got to much change. When I went to her and asked about it, she was really surprised that I came back. Hell she even knew I had given her a ten and was really thankful that I came back. I wonder how many people would have done what I did? I doubt most people would have done what I did. I'm not talking about just theist but I am afraid many atheist would have walked away without returning the incorrect change. I wish more people understood that money is important but not what we should really focus on. Sometimes I wish I could be like the people that have ruined the economy but I can't be. Yeah, money is important to me but not so important that I screw someone over making less then I do.