With no religious intent, I feel that Sunday' should be designated a day of rest for (almost) all.
Too much stress at work, too much pressure at home and at school. If the big shops closed a) everyone could use the day to relax and spend time with loved ones, football/rugby/cricket, sons and daughters or just unwind in the garden, in bed etc and b) the streets could be returned to the small shop. Shopkeepers play an important part in society, they know who is who, where places are, whose children are behaving and whose aren't, who is trading alcohol and drugs and they are a useful adjunct to the police.
Everyone is happy? probably not but the small shopkeeper gets a share of the available trade and everyone is relaxed and not rushing around, with no pressure to spend what little money we have left.
Why is this idea important?
It is one way of restoring a sense of unity to the family unit, curbing the supermarket hold on the public, creating opportunities for the smaller shopkeeper who battle against the aggressive prices of the supermarket and maybe help the return to a sense of community.
And maybe even cut the number of working days lost due to stress related sick leave.