So, according to the bible, God created the world in 6 days and rested on the seventh. This is, quite simply, the reason there is a weekend.
Now, let’s say I’m looking at this from a very practical, non-religious point of view. The weekend is the time of rest (especially Sunday, of course) when one is expected to relax and recoup. The last thing anyone wants on their day off is the office calling with a bunch of demands.
Given that… isn’t it inconsiderate to hold church services on Sunday? It amounts to the whole world calling God on God’s day off, demanding that God do stuff. Sheesh, makes me glad I’m not a deity.