indeed.
Also, I feel bad for new tanks when I roll as a DPS and you can tell they are literally afraid. Then someone makes a dickhead comment and they play worse because they are scared. So what if you can't speed run your 400th Brayflox Run? Teach them, be patient... make it easier for them if they are already having a tough time. Take a sec to actually examine them... if they at about 5k HP, its a pretty dead ringer that they are inexperienced and if you REALLY have that much of a problem with that, thats a you thing.
Its not always the tanks fault, and it shouldn't be the only job that gets stress via the role they play in game.