['I confronted a cashier the other day about over charging me but it turns out that I was wrong.', 'Ouch!  That had to feel embarrassing!  Did you apologize?', 'I did profusely!']
That's good.  That shows your true character.
I was shopping the other day and was convinced the cashier had over charged me. I confronted her and finally asked to speak to a manager because I did not feel that I was getting any response. The manager proved to me that I was wrong.