Are you a Ray-bans man or an aviator kind of guy? Tortoiseshell or plain-black frames? All of these are good choices. However, the neon-green freebies your co-worker gave you from an EDM concert last summer are not. Think about what you want your shades to say about you. (No, really. Think about it.) Whatever you decide, never use your sunglasses to creepily check out girls. It’s gross. And pervy. And painfully obvious. If you're going to do it anyway, you’d be wise to check the opacity of your eyewear first.