Many artistic types are perfectionists of one breed or another. I hate it when people call me a perfectionist because I don't think of myself that way. I'm capable of ignoring things that aren't perfect, but this is really only true if they are things I have deemed "unimportant," so, like cooking, my physical appearance, housecleaning, things like that. When it comes to writing, it can be very difficult to turn off the perfectionist impulse.
On the one hand, it's actually important to be a perfectionist. If you're a sloppy creator and you send things out constantly without them being ready, you're not going to get very far. You may or may not get better, but I suspect you will get better less quickly than the people who just have to look at their piece one last time before they submit it or those who can't stand to see a spelling error in a final book and send a list to their editor of changes they want made to the second edition.
Being a perfectionist means that you're going to be measuring yourself against the best of the best, and that you're always going to be striving for more. This is a very good thing. It means that you have a sense for what is good. You have an "ear" for good language and plot, that you demand your characters feel real on the page. It means that you really listen when you get feedback, and that you're willing to do more than fix a couple of comma splices. You can start all over and really make all the changes necessary to address the problem.
Being a perfectionist can also be the death knell for a creative career. I've seen perfectionists who simply can't send anything out. Ever. They're too worried it's not perfect enough. They are always waiting for someone to point out how much it's like this thing or that thing, and it's not as good. Or it's just too derivative.
I've seen creative perfectionists who literally delete everything they've ever written (or burn it, in the old days) and I want to shake them (or just save what they're throwing out). I've seen creative people give up on careers entirely and do something else where they can turn off the perfectionist bent because it doesn't matter. (Everyone has a choice, of course, but this still makes me sad.)
Being a perfectionist can also mean that you end up never starting. You sit down and you think about how great you want this to be, and then every sentence you imagine in your head doesn't live up to your imagined perfection (or your imagined painting or music or anything else) and so you shake your head and stand up and you keep trying for a while, but eventually you give up.
Being a perfectionist sometimes means that no matter how many people tell you that this is good, you don't believe them. Even if you get good reviews and you're published and making money, you don't consider yourself a true artist, you're a "hack" instead. Someone is always doing something better than you are, and you always compare your worst to their best.
I observe these tendencies in myself and others and all I can say is that we have to find a way to keep it in balance. We need that perfectionist tendency to strive for better every day and to make the creative leaps that people who don't take risks will never make. But we also can't let it destroy us.