I have said no to job offers that required me to work 5 days. I explained how it was old-fashioned and that people with kids needed time with their kids too, that part-time work was the way of the future, and that people aren't fully productive for 40 hours a week anyway, so a 4 day work week generally gets you more than 80% of the productivity of a 5 day work week.

They fully agreed, and yet they still couldn't hire me for less than 5 days. The job sounded great, but I said no. It was a good decision.