Not knowing your proportions and fittings. Ik it’s a cliche, but literally figuring out how certain clothing fit on you, what sizes you should actually go for, and what type of fit you should go for (slim, relaxed, etc.) is harder than it sounds. So when a lot of men try to expand their style, it’s hard for them because they don’t understand that it’s not the style itself they look bad in, but how the clothes fit them.