Perfectionism is a personality trait, which can be an endless pursuit of high standards in every area of our lives, but can also be a 'disorder' like condition or a phobia, akin to 'Fear of Failure'.
The trait of perfectionism constantly makes a person judge, compare and criticize suboptimal decisions or mistakes in any aspect of the daily routine.
A person starts having mental difficulties, striving to do everything the perfect way, but falling short eventually.
Perfectionism is a voice in our head, constantly fed by the media and society's ideals, coaxing us into doing things in the best way, to get the desired results.
It is useful in its purpose but in extremities can have negative effects on the body and mind.