Opening hours?

I always have difficulties to remember if the shops are open on Sundays or not here in Finland. In the summertime they are and then also at Xmas time, but why they are not open rest of the year evades me completely. And why do the shops and supermarkets close at 6 pm on Saturdays? Weekends as it happens is the time people are free, so they can do shopping, spend their money in the supermarkets.

Another thing I keep wondering about it the logic in lunch-hours, and this applies not only it Finland. If you work fulltime the most convenient time for you to run some errands to the post-office or the bank for example is many times exactly when there is just one person to take care of your business. Of course they do have to have lunch-hours too, but hey, are they not in customer care so where is the logic here, least personnel available when most customers? Should they not be there when the customers are able to come? Get some extras to come during the lunch hours, many people would be happy to have a halftime job. One comes in for the morning, the other for the afternoon and they both are present during the lunch hours.