Several years ago I was a clerk in a video store, and I remember having to work Christmas Day the first year I was there. The owner was in prison, and instructed the manager to be open 365 days a year.

At least the store didn't open until noon, so I could be at home with my family for the morning hours and an early dinner, but still. We had very few people come in, they only made enough money to cover my wages for the day. They still had to pay the electric bill for the day too, so actually lost money.
I don't think anything should be open on major holidays like Christmas, New Year's Day, Easter and Thanksgiving except for of course hospitals, police stations, fire stations, and the like. Oh, maybe a few gas stations as a lot of people travel on holidays, but regular stores like Wal-Mart or K-Mart, or worse yet video stores, have no need to be open. It's just store-owner greed.