Aim for the moon and you get to the stars. Perfectionism is when you're disappointed with those twinklers because, they're not the moon!!
The belief that perfection is a real possibility rather than something to aim for, is a hard task master. It means the likelihood of spending most of your life in a state of ever burgeoning disatisfaction. Until you crash in some way. You probably will.
Unless you think you're perfect, then you'll just be a pain to everyone else.
Perfectionism is the underpinning to many mental health crises, neuroses mainly. It often becomes depressing, as it is exhausting to the nervous system. Many people in this state of mind feel they have low self esteem. Not necessarily.
Our default is self esteem, we tend to notice if that's being undermined, by falling short of impossible standards.