credit cards

I have one very good habit that I always check up each item on my credit card bill. I am always suspicious that I can get overcharged.Doesn't happen often but it happened couple times.I came home tonight and have opened my credit card statement. First thing what took my attention was a $100 charge from a gass staion. "Do I drive a bus?", that was my first question.Nope.I have called custumer service and put a disput on this item. What I am trying to say is ,that everybody should pay a littel more attention to casual things like this and save some money.