My mom wwas given extra money by the teller at a bank drive through. Being the honest sort she called the bank to report the error. She drove back and returned the funds. The next day week she received a call from a business saying her check had bounced.

It turns out that the bank deducted the reported funds after her call. Even though they put them back after she handed over the cash it was a large enough deduction that it triggered overdraft charges. The bank refused to take off the fees. So much for honesty and so much for intelligence on the part of the bank employees.