Ferruccio Lamborghini made tractors until Enzo Ferrari insulted him

A wealthy manufacturer of tractors and air conditioning and heating units systems after World War II, Lamborghini was an enthusiastic owner of sports cars. After owning and driving a Mercedes-Benz 300SL, a Jaguar E-Type, an Alfa Romeo 1900, a Lancia Aurelia B20 and a Maserati 3500GT, he bought his first Ferrari, a 250GT. He became a Ferrari enthusiast, eventually owning three. However, he had recurring clutch problems, and eventually brought his complaints to Enzo Ferrari. Ferrari insulted Lamborghini, effectively stating that a tractor manufacturer was not qualified to criticize Ferraris. Affronted by Ferrari's reaction, Lamborghini began to repair his clutch himself, at which point he noticed that some of the clutch components were the same as the ones he used on his tractors. He replaced the clutch with one built to a stronger specification, which solved the problem. Lamborghini then decided to build faster and more reliable cars than Ferrari and to prove that supercars did not have to be as temperamental as Ferraris.

http://en.wikipedia.org/wiki/Ferruccio_Lamborghini