Unfortunately the community seems extremely unforgiving when it comes to tanking. Alot of people will be cool and understanding and help you out, but overall my experience has been negative.
I played WoW for 7 years and I was in one of the most hardcore guilds you can imagine. And even *I* am surprised at the extreme elitist douch3bag attitude most of the tanks + other PUG groups display. Its like... if you dont already know 100% what to do and execute it with perfection you will get scolded hard.

Example: Entering Ifrit HM for the 2nd time, after having main tanked him just fine once allready - another warrior asks me to stun. First time was with a paladin so he did all stuns. When I asked "Only me or do we rotate?" he answered with "..." and then proceeding to tell me what to do in the most condecending way possible as if I were a child. When I failed one stun that caused a wipe (One single stun missed) he proceeded to flame me. We made it in the second try though. Luckily the Ifrit axe dropped and I won, KARMA!