Being able to take Critique only makes you cool and awesome if you can do it without the passive aggressive attitude towards the person who gives it to you.
Tacking "But I appreciate your feedback!" or "By the way, I really respect you for your time!" onto the end of a review reply where you're obviously pissed at the reviewer for daring to say anything bad about your fanfic, and make excuses for plot problems (protip: They should make sense in the story to begin with) or typos or shallow characters or whatever.
Of course, if you disagree with a reviewer, fine. It's your fic and yes, you CAN write it however you like. But if you post it online, you will get opinions, and if you're going to reply to the opinions you don't feel like paying mind to, do it without the snark if you really appreciate/respect them.
A line of words is just a line of words. When you obviously don't mean them, they might as well not be there.
P.P.S. Sucking up to the reviewer by telling them you love their fics only makes it worse.