Background: Andreas Nikolaus "Niki" Lauda (born 22 February 1949) is an Austrian former Formula One driver and a three-time F1 World Drivers' Champion, winning in 1975, 1977 and 1984. He is currently the only driver to have been champion for both Ferrari and McLaren, the sport's two most successful constructors. He is considered by some as one of the greatest F1 drivers of all time. More recently an aviation entrepreneur, he has founded and run two airlines (Lauda Air and Niki).
Context: Having joined Parmalat-sponsored Brabham-Alfa Romeo in 1978 for a $1 million salary, Lauda endured two unsuccessful seasons, notable mainly for his one race in the Brabham BT46B, a radical design known as the Fan Car: it won its first and only race at the Swedish GP, but Brabham did not use the car in F1 again; other teams vigorously protested the fan car's legality and Brabham team owner Bernie Ecclestone, who at the time was maneuvering for acquisition of Formula One's commercial rights, did not want to fight a protracted battle over the car, but the victory in Sweden remained official. The Brabham BT46 Alfa Romeo flat-12 began the 1978 season at the third race in South Africa. It suffered from a variety of troubles that forced Lauda to retire the car 9 out of 14 races. Lauda's best results, apart from the wins in Sweden and Italy after the penalization of Mario Andretti and Gilles Villeneuve, were 2nd in Montreal and Great Britain, and a 3rd in the Netherlands.  As the Alfa flat-12 engine was too wide for effective wing cars designs, Alfa provided a V12 for 1979. It was the fourth 12cyl engine design that propelled the Austrian in F1 since 1973. Lauda's 1979 F1 season was again marred by retirements and poor pace, even though he won the non-championship 1979 Dino Ferrari Grand Prix with the Brabham-Alfa. In the single make BMW M1 Procar Championship, driving for the British Formula Two team Project Four Racing (led by Ron Dennis) when not in a factory entry, Lauda won three races for P4 plus the series. Decades later, Lauda won a BMW Procar exhibition race event before the 2008 German Grand Prix.  In September, Lauda finished 4th in Monza, and won the non-WC Imola event, still with the Alfa V12 engine. After that, Brabham returned to the familiar Cosworth V8. In late September, during practice for the 1979 Canadian Grand Prix, Lauda informed Brabham that he wished to retire immediately, as he had no more desire to "drive around in circles". Lauda, who in the meantime had founded Lauda Air, a charter airline, returned to Austria to run the company full-time.
Question: Why was he so disastifeed with his career?. Whats the answer?