The HVAC system in my old house. When I bought it the guy at the hardware store said "it will pay for itself in 5 years!" I did not beleive it, but I need heat so I bought the system on credit. Exactly 5 years to the date of purchase, that Heater jumped right out the basment, drove my truck all the way to the bank in New Jersey (where my credit card monthly payments were sent) and payed the whole card off. I don't know if it robbed another bank on the way or scared the teller taking the money when she/he saw a fucking gas furnace driving a truck trying to pay a bill or what, all I know is that my next statment showed a balance of $0. I never saw that heating unit again, but I'd sure like to thank it for paying for itself.