This casual pairing of a dark green shirt jacket and shorts is extremely easy to throw together in no time, helping you look amazing and ready for anything without spending a ton of time searching through your wardrobe. For a dressier take, why not add loafers to the equation? This combo is a really great option, especially for autumn, when the temps are dipping. So if you're hunting for a nice and mature pairing for a 20-year-old man, this one fits the bill.