Why do MMORPG communities always suck?

I have played EVERY single popular MMO known to man (both free and pay-to-play) and not one of them had a decent community. I remember playing this one small MMO which had only had a few hundred players and it was alright for a while, but once the game was advertised more, then a lot of shitty people came and ruined it. Why?

in most mmorpg's(LIKE IN REAL LIFE) people aren't going to come up to you and talk to you...YOU have to talk to them and be friendly or else no one is going to do anything...and you'll be lonely...so just talk to the ppl