They say nobody is perfect and you believe it. Then you come across the perfectionists! There is only one way of dealing them - do as they say. Anything else would only mean inviting trouble. In fact, they are like super-humans who only want to defy all rules of imperfection. In other words, stay perfect all the time! Who does that? As their friend, you feel helpless and annoyed, and hope that someday they'll learn to take it easy.
Remember the time your homework was incomplete and you requested your friend to not submit his/her work? They didn't listen and you got screwed.