From my experience first hand I can say that just for being a fan of the away team I have been called all sorts of names, sweared at, gestured too and chanted at.... Thats not what I want when I watch sports.
I was at the Arsenal vs Leyton Orient match at the Emrites last year and there was even a kid about 8 years all using the N word to describe some of our fans of a particular race... In that particular games, many fans got chucked out and a fight broke out between a drunk Arsenal fan and a security guard which ended up with the police getting called in to arrest people...
Going to a soccer game makes me feel embarrassed to be a Brit, I am extremely un-patriotic as it is so that doesn't help.... I root against England in pretty much every sport, since especially in football the players that represent my country like John Terry are an embarrassment.
I don't care if you think this is weird but in the baskteball and soccer world cup I generally support the USA instead because I am more connected with your sports and culture.... Especially in Basketball because the USA team includes most of my favourtie players like Bron, Wade Durant and Howard.
Thats what I meant by abuse and racism and thats why I don't like soccer.
However, the fact that you enjoy it is great, if you like it go ahead and support Chelsea or whoever, just don't expect me to tune in with you and watch it.