I find it quite funny, and over the years I've met worked with or am friends with a lot of the personality types on BBT. I suppose you find stuff you can identify with funny.

It's hugely more amusing than the IT crowd which
I found cliched, if somebody quotes 'have your turned it off and on again' I'll electrocute them, although I did spend lots of time pausing an episode and looking at the contents of the shelves.
there's other stuff in the it crowd I have a problem with as well but life's to short :-)

Friends was ok to waste a half hour but I'd never go out of my way to watch it.