If a guy stares at you like this.. whats he thinking...??????????????!!!?

if a guy is leaning against his locker staring at you...FOR LIKE A MINUTE.. with a concentrated but still kinda blank look on his face ...whats he most likely thinking about...are they nice thoughs or dirty or something else? ... (btw i wasnt looking my friends hilary and jess told me)..hes done it more then once