A properly sized jacket should go down to the middle of the buttocks. Buttons, a matter of style. It is generally recommended to only do up the first button of men's jackets. The tailored fit of a jacket refines your silhouette and flatters the shoulders. The most daring can try stripes, patterns or bright fabrics for a fashionable look. Dress-down Friday? A black men's jacket over raw jeans has become a classic of cool workwear.