As a tank main...if that was said to me, especially if nothing went wrong, I would get defensive. Why? 99.999% of comments like that are sarcastic insults when directed at tanks. I've been berated many many times for nothing at all or for other people's mistakes; I've considered several times to not tank for randoms, but I still do because I can't stand bad tanks even more than the insults. (bad thing about being a good tank, the bad tanks are even worse to you than other jobs...same thing applies to heals seeing bad heals and dps seeing bad members of their job)

If you want to compliment a tank, just make sure it doesn't have sarcasm in it.