“You could’t polish shit” is a popular aphorism roughly comparable to "putting Lipstick over a pig" (While "a turd" is much more usually applied). Even so, the TV display Mythbusters showed that anyone can, in reality, polish a turd. Shit occurs means that bad happenings in life are unavoidable. https://ass59414.theblogfairy.com/35913317/the-smart-trick-of-bitch-that-no-one-is-discussing