I guess it depends on the industry you are in. I was at a law firm, and they charge by the hour so more hours=more money in that business. We were also expressly told it was a job requirement to work during vacation if any work arose on our cases, and that frequently turned out to be true: I would spend as much of the vacation day as I could with my family, and then work from 9pm to 4am (or sometimes all night) on my laptop before sleeping a couple of hours and starting the next day, not because I thought I was "essential" or "special" but because I was told I had to by the person paying my paycheck. I was even told in that job I had to work when I had actual pneumonia, and when my grandmother passed away. Glad to be now in a different job that allows "real" vacation (and sleep). And it is not all in my head: I do actually know of someone who was let go because he took all of his vacation days and that was seen as a sign of poor judgment/work ethic.
Not trying to throw a pity party, but I just find it really harsh that so many people here are saying some variation of if you work on vacation it is because you either have too high an opinion of your own worth or because you don't understand how your own job works. Not every job gives you a choice.
