I sort of like the conveinence of having things open everyday. That way, in case I forgot something or need something, I can run out and get it. I'm speaking in terms of grocery as I don't shop often for other things.
I lived in Florence for a year, and it was like that there. By 6:00PM, the streets were empty. Except for the tourists who were like "ahh, what happened?!" lol And then Sundays everything was closed. On top of that, there was some sort of weird business schedule that I could never figure out. Sometimes businesses would be closed on Mondays. Sometimes they were open. Sometimes banks would be closed on Tuesdays, sometimes they would be open. I could not figure it out, though I'm sure there is a very simple explanation.
After that year, and the next one, which I spent in London, Greece, and Poland, I must admit I have come to appreciate having the conveinence of stores being open daily, often 24/7.
I, too, am an atheist, and so Sunday for me is just another day. I actually think that stores could take a day off, easily, during another part of the week when most people are working. But, Sunday, for me would be an inconvenient day to have things close. I do my shopping then!