I jumped online today to check my checking/debit account balance, and noticed something fishy.
I went to Joe's Crab Shack for a birthday party, and we all split a $189 bill (before tip) between 5 people. I paid $50 to cover myself and someone else.
I look on my bank statement today to find that not only was I charged $50, I was charged an additional $139 (which equalled the remaining amount of the bill)! I saw that everyone else paid for the remaining share, so how I got charged the extra amount is beyond me.

Glad I caught that one!