Just a simple critic.

"Criticism may not be agreeable, but it is necessary. It fulfills the same function as pain in the human body. It calls attention to the unhealthy state of things." - Winston Churchill

"In many ways, the work of a critic is easy. We risk very little yet enjoy a position over those who offer up their work and their selves to our judgment. We thrive on negative criticism, which is fun to write and to read. But the bitter truth we critics must face is that, in the grand scheme of things, the average piece of junk is more meaningful than our criticism designating it so. But there are times when a critic truly risks something, and that is in the discovery and defense of the new." - Anton Ego, Ratatouille

On Constructive Criticism: How there is a difference between trolling, hate mail, and true constructive criticism. (Not written by my hand, but it is an excellent description of what criticism is and aims to do.)

As soon as you make something, one day, someone, somewhere is not going to like it. It is a fact of life, and it's just something which you should be able to take when you post something on this site. If you can't, cry me a river and then get. Off. The. Site. Don't start saying how you hate people who dislike your work, don't declare them Satan and never, ever retaliate by trolling their own stories or suchlike. That will do you no good. What you need to do is simple: Take a look through the review. Is there anything in there that isn't swear words or abuse? If not, you've got yourself a flamer, someone who dislikes your story purely because you killed their favorite character, don't ship their favorite couple, or didn't ruin the life of someone they hate. You can safely ignore these. The internet is anonymous, so people tend to be a lot nastier than in real life, so don't take it personally. Pay them no mind. Should the reviewer insist, block him/her, again it's nothing personal, they're just being a troll, basically an advanced kind of flamer

If however the reviewer actually claims to have a point, take a closer look. Say the gist of a review full of swear words is that X and Y would never get together so quickly. Consider the following: if confronted with the situation you place your characters in, say seeing your love interest bathing naked, how would the character react? Scream? Faint? Run away? Join him/her? Take into account how much characters know about one another, their ages, their personalities, and most importantly: Don't just treat them as action figures who dance at your command (I could go on about this for much longer, but that's another comment). You should always keep in mind that maybe the reviewer is right, even though the review itself is loaded with swear words, insults and more.

Another kind of review that is hated a lot is the 'Grammar Nazi' kind. If you get one, DO! NOT! IGNORE! Nothing breaks the flow of a story as much as a badly misspelled word or shaky grammatical construct. Just go back and fix it. This, in my opinion, is the most stupid kind of review to hate. There seriously is no reason why; these reviewers are so obviously trying to help you, hating them is kind of like dangling of a cliff and then feel offended when someone offers a hand.

Lastly, for some strange reason reviewers are just as insulted as some writers when confronted with the bad quality of their reviews.