The unfinished beginning has more potential than the perfect plan never touched.

An untouched plan has no potential in any practical sense, because potential requires a path from here to there and nothing has been built. A messy beginning, however poor, has direction, feedback, and momentum, all of which are the raw materials of anything finished.

Compare what you have started badly with what you have planned perfectly. Put the next hour into the first category. Perfection in planning is largely a way of enjoying a project without risking it.