Um, hello? Rational side of your brain? What made you think that showing stomach in the business world was appropriate?
Oh, I'm sorry- perhaps you didn't realize that you have a flesh belt? Did you mistake it for your leather braided one from the Gap? Did you forget that you work at an office/restaurant/store and, in fact, you do NOT work at the local strip club?
Or maybe you think showing belly at work is no biggie. Did you also notice that you weren't getting promoted or a raise? Do you think any supervisor would view you the same way as the equally qualifed person next to you who dresses appropriately? I have news for you: you are very, very wrong.