Whoever thinks a faultless piece to see,
Thinks what ne'er was, nor is, nor e'er shall be.
—Alexander Pope, An Essay on Criticism
Perfectionism is something that can be truly paralyzing. A project is a series of branching paths and getting to the desired end goal would seem to require picking the correct path at each decision point. These constant decisions become a source of friction and anxiety leading to nothing getting done.
It turns out however that the paths intersect at many unexpected points so each decision is probably less critical than it seems (identifying truly critical points is an important skill however). Additionally, the end goal that was held in the beginning is not necessarily the best one, and going down alternate paths may be the only way to discover other end states.