ISF
Insufficient Funds (lack of money)
Bobby Chong is looking to buy 2 doughnuts for 50 cents each. The cashier lady says that will be; a dollar seven total. Bobby Chong whips out the B.C(Bank Card), swipes, punches in the pin and waits for the thumbs up for approval then 3 letters in Capitals show up on the machine; ISF. Cashier shakes her head in shame and pitty. Bobby curses and walks away for the counter doughnutless; and realizes that he will never step foot in another Tim Hortons again due to ISF...$1.07 damn. How embarrassing.