What are the worst fashion mistakes people make?

Women who think it's cute to have a fat belly and still wear crop tops or tight shirts with muffin tops hanging over the tops of their pants. Wear a waist trainer for god's sake. And older women like me who wear very low cut shirts and have wrinkled chests. Nothing wrong with wearing tight sexy clothes, and dressing young and stylish, but the wrinkled chest isn't going to get you a hot date.
Men who still wear their jeans hanging down their butt with underwear hanging out. Ugh!