I don't think there's a college student alive who hasn't heard the term "peer review" at some point in their education. Even if it's just something they had to do in some class and forgot about later, everyone has had some kind of experience with peer review. Some, like me, went into it with an ego so enormous they couldn't possibly learn from the activity because, clearly, their writing was already perfect. Others, and I have been this person, too, go into peer review with the most self-deprecating attitude and are so prepared to hear the worst, they can't accept any positive feedback. Wherever you are on the scale, peer review is important, for whatever you're working on.
Most people think peer review is a writing concept. Give your essay to a friend and they will tell you what's good and what's not and then you fix it. The concept certainly lends itself well to writing, but what about other creative avenues? Shouldn't a video game designer be as free to get his or her friend's feedback as a chemist planning an experiment? Getting feedback from other people makes everyone better. Peer review isn't just about revising an essay, it's about making whatever idea you have the best it can possibly be.
Part of this improvement process is, of course, the feedback itself. Whether your ego is enormous or tiny, getting advice from peers and friends makes you better. Sometimes, you need that person to take a pin to your ego and tear your work to pieces. I will be the first to admit, I tend to become too attached to my work, to the point where I can't accept negative criticism on it. However, this is precisely the reason why I need that negative criticism. I need someone who will tear through my work and then hand me the pieces that are left and say, "it's all good, just try again." When I recreate it, it's always better. Maybe you're not like me, maybe you're the person who needs someone who believes in you and your work and who will help you see how good it is. Wherever you are on the scale, feedback can help you make your work better. As long as you're willing to take it.
Getting feedback from your peers is not a waste of time. In fact, it's something that can make you better, in whatever discipline you're pursuing. I know it's easy to say, "they just don't understand," or even "I just know more about this than they do," but don't discount peer review because of pride. I know, because I've done it, and my grades and abilities suffered because of it. Accept the advice from your friends and classmates and use it to make your ideas the absolute best they can be.