Some people hated school, but you loved it, because success was quantifiable -- you had assignments, grades, feedback, and a teacher whose job it was to provide positive feedback and a pat on the back for a job well-done. You might have been a teacher's pet, or maybe you were voted “Most likely to succeed” in the yearbook. The structure of school and easy equation of "work hard, do well, be rewarded" is a comfort for most perfectionists.
In the real world, success is measured differently. Everything is structured differently. And while you might not ever tell anyone, there’s a part of you that misses that world where it was possible to get an A+ and call it a day.