Here in Bulgaria almost nobody realises that the week could start at a different day than Monday. (See the link in the first post why it is in Bulgaria that way)
Me too didn't have a glue of it unless my daughter returned from Israel a year ago and told me: "Hey! There's Sunday the first day of the week! And we have problems (in work) with it. "
After that we talked about
how Jews had ruled even our calendar...

And I see that's not the Jews (only)

The next time I noticed the Sunday is when I posted this thread

Now I know more and my horizons got wider.