Why do some Man United fans think supporting a big club makes them better?

the sad thing is that if man u were not so successful then most people who support them would not . i live near london and since chelsea have won a few tropies you would not believe the amount of people who have come out of the wood work and now claim to be life long chelsea supporters the same goes for man u supporters , theres a joke down here and it goes how can you tell a man u supporter , answer by his es accent