Admit it...how many times have you checked your work e-mail during times you weren't working? I'm guilty of it, too, many times, and the latest research says that it's a really bad thing to do. Why? The answer is simple. Checking e-mails outside of work hours increases stress. So, the more you do it, the more stress you feel and the higher level of stress you maintain on a consistent basis, which is bad for your body and your mind.