Receiving criticism is one of the hardest parts of writing—harder, perhaps, than finishing that first draft. But before we get into it and what makes it such a chore to endure, we're going to have ourselves a little Greek Mythology 101 lesson:
More than likely, you've heard of a vain pretty-boy named Narcissus. How vain was this guy about his renowned good looks? So vain that he most definitely would think that Carly Simon's song was about him. In fact, Narcissus was so obsessed with how great he looked that he died by drowning in a lake because he just couldn't stop looking at his reflection in the water.
While most people aren't as, well, narcissistic as Narcissus (Justin Bieber not withstanding), we do inherently have this aversion to having our flaws pointed out to us. This goes doubly true for us writers and the pieces that we work so hard on. Like all people, we don't want to accept that we may have flaws, and moreover, we don't want to accept that something that we spent time on—something that we poured our blood, sweat, tears, and hearts into—may have flaws as well. But alas, at the end of the day, we must face facts: no, the Fifty Shades of Grey movie will not bomb at the box office; no, Hermione x Malfoy is in no way, shape, or form canonical; and no, not even our precious, precious writing that we love and nurture with all of our hearts is safe from flaws. And, no matter how much you kick and scream and offer your firstborn to the gods, every decent editor, beta reader, and reviewer who comes along and reads your work will point it out.
But the thing is, it's a good thing that they're pointing out the flaws in it. Your work, just like you yourself, cannot hope to be improved upon unless you first know what you're doing wrong. And, unless you're spending five hours every night working on fanfiction just so your dream of Hermione and Malfoy learning that they were meant for each other can be realized (which, okay, isn't an unworthy cause), you'll want to improve. Every artist who takes his or her craft seriously—whether he or she is a writer, a painter, a filmmaker, or musician—wants his or her work to be the best that it can possibly be, for only at the true completion of a work (as in, the been-fed-through-the-redo-grinder-so-man
The same goes for when you're on the opposite side of the creation chain—when you're the viewer of a piece that someone has painstakingly assembled and bravely set it out in view of the whole world for it to love and cherish or hate and bash. Sure, sometimes it's easier (and heck, funnier) to make fun of a work instead of intelligently discuss ways in which it could be improved (RE: Fifty Shades of Grey), but the next time you're tempted to spend a half-hour on a Tumblr rant about what awful characters Christian Grey and Ana Steele are, think instead about how they could be improved. Do they need more character development, or are they just plain unsympathetic (or, in this case, both)? What aren't they doing for the story? What can be changed about them so that they can effectively do something for it? Focusing on how a work could improved instead of how terrible it is not only adds some positivity to an otherwise negative topic, it also helps you sharpen your critical eye—the same eye that you use when you work on your own pieces.
In closing: accept constructive criticism gracefully. Listen to it; keep it in mind for the next time you work on the piece or start a new one. And when dishing constructive criticism, remember to keep it constructive—as in, helpful and supportive and not mean-spirited. There are more than enough meanies out there looking for someone to tear down; be the bigger artist (and person) and root for your fellow artists (and people). Share your tips, and listen to theirs. Learn. Make mistakes. Learn some more. Improve. Grow. And hey, don't forget to sit back and enjoy the journey, too, eh?