A: His email inbox

Never read his e-mail, but a glance at his in box can give you some insight into the kind of person he is. A guy with a tidy in box probably manages his life well, while a guy who has lots of e-mails open may have trouble prioritizing. And no matter how neat a guy is, if he never deletes a singe e-mail, he will probably be emotional and sentimental in his relationships. (Cosmopolitan)