Why are people okay with shopping on a weekend?

I'm from Greece and this is something that I've found inconvenient compared to back home. It seems like the system here is a remnant from the times only the man worked and the housewife could go to the shops anytime.  But now it's not feasible. In many places, shops have a strange office-hours schedule which never made sense to me for modern times. Which leads to people having to wait for the weekend to do their shopping. I find it inconvenient and stressful that I have to do that. Shops and shopping centres get so overwhelmingly packed. In Greece, the days alternate. Shop owners close the shops for the afternoon and reopen them in the late afternoon until 9pm or so. But next day they open them only in the mornings. Then Saturdays are open most of the day and Sundays they're usually closed.