It depends on how you play.
During the time i played, i never joined raids or anything, i always 5 manned my instances, and to me they were all challenging and fun to play.
I tried raids but they never did anything to me. Indeed, they were way too easy, messy and frankly, pointless. Plus i just couldn't stand playing with those people.
I enjoy the fact Blizzard has made a casual gamer friendly enviorment. One of the reasons i never wanted to try MMORPGs in the first place is that i didn't want to commit my life to a video game. The trade off is the horrible community. I can't count how many times i've met level 60 paladins who never trained spells, and we all know Blizzard has one of the worst gaming communities, right next to Counter Strike fans.
What you need to do is actively seek out good players. If you find somebody you enjoy playing with, mark their name down and try to see if you can play with them again. Joining a RP server made things a lot easier. No, nobody really roleplays, but there's a higher chance to find more mature and smarter gamers.
Multiplayer games are what you make them, and the people you play with make all the difference. A bad apple on a 5 man scholomance run can turn a couple hours of fun into an afternoon of pure hell...