It’s funny you give out about supermarket opening hours when being English - Sunday trading laws are arcane in England too!
When I moved back to Italy I had forgotten that shops close between 13 and 15:30. Every country has their own little quirks
There were some weird exceptions to the rule, too; in particular you could buy alcohol on trains.
I kinda miss the old Good Friday laws, it made it a great day for parties as all the pubs were closed.