Dear Keke and Kat: Coworker Ruining My Job

We've all dealt with a less-than-ideal coworker situation. Sometimes your colleagues just aren't your favorite people, and there's nothing wrong with that! But when someone is totally wrecking your work experience and affecting your productivity, there's a problem.

Should she confront this guy? Quit her job? Get HR involved? Complain to her boss? What would you do? Have you had this happen?