No matter how laidback your office is, don't wear flip-flops! Flip-flops rank as the No. 1 office wardrobe crime for a reason. For starters, nobody wants to look at other people's feet all day. Secondly, too many people think that flip-flops, like fine wine, get better as they age. Sure, you may think of them as broken-in, but what they really are is old and smelly. Plus, the slappity-slap sounds flip-flops make can drive co-workers up the wall. If you need any more reasons, try these: They're unprofessional, unattractive and unsanitary. And we realize that was a lot of negatives to use, but that's just how strongly we feel. No flip-flops!