Perfectionism is a most dreadful disposition
I'm actually serious about this one, as a former perfectionist, I know all too well the blight it has cast over my own life from a very early age and the seemingly constant disappointment it brought me. We, as humans, are not designed to be perfect, we are flawed in order to learn and grow, it's how we obtain the necessary skills to become functional adults, through failure as children.
Imagine a way of being that expects to do everything perfectly, first time, every time. How on earth is that humanly possible yet there are many people who do operate this way, you know those people who gain 97% in an exam and they are congratulated but their response is to say that they could have done better - not only de-valuing the compliment but also undermining themselves. We all know someone like this, it's not the same as striving for being a better you - that's different.
What happens to neurology when a perfectionist has this kind of self-talk (we all talk to ourselves and often it's not nice). What should happen is the happy hormones, endorphin, dopamine, serotonin, should be shaken into the most delicious cocktail and released into the body nurturing every cell allowing us to feel fantastic. What actually happens is that this release of feel good doesn't happen or is significantly dampened down. And even more relevant is if stress hormones, mainly cortisol (but it is also a cocktail but a toxic one in large doses) are released frequently, say prior to an exam, the brain considers the most frequently used state of being and adopts that one. Plain speaking this means that in the absence of any particular cocktail that is clear in its message the brain will opt for the most frequently used. In my experience, those people who are perfectionist love a toxic cocktail.
What's the antidote - well the first step is to recognise that you are potentially a perfectionist, then ask yourself if this way of being has been useful to you - absolutely there is a time and a place where perfectionism shines, but not for everyday; for turning the labels round on all your jars, studying or stressing to a point where you can no longer think straight, doing and redoing something over and over again because it's not quite right and never actually finishing it because it's not perfect when good would be good enough.