An accountant was taking a cruise on a luxury ship. Suddenly, she saw another passenger fall overboard. Panicking, the accountant screams: "Help! Help! Someone's fallen over! Someone's fallen over!"
The ship's second mate hears her and shouts: "Which side did they fall? Port or starboard?"
Accountant: Port...star...what?!?? (Then frantically points to the left) DEBIT SIDE! DEBIT SIDE!