I was wondering..?

  So I've read several places that the exercise you get at work doesn't count.  That somehow your body adapts to it and it no longer has an effect on you body.  I was wondering if that is true or not.  I honestly don't think it is, if it was wouldn't your body adapt the same way to conventional exercise?

  I was wondering, because while I don't exercise, I do work as waitress, and it can be a pretty decent workout some nights.

I don't think that's true at all. Your body burns calories even if you were in a coma... so moving around waitressing would definitely burn more calories than if you were sitting in an office.