The sketch discarded by its maker can be the part another person finds most alive.

What a maker throws away is often what a stranger finds most alive. The discarded sketch was rejected for failing to become the intended thing, but a viewer arriving without that intention sees only what is there, and what is there can be loose and immediate in ways the finished work is not.

You are a poor judge of your own offcuts. Keep them rather than deleting them, and let someone else look occasionally. The same holds for the parts of yourself you consider unfinished or unpresentable; other people frequently find those the most human thing about you, precisely because you were not managing them.