I agree. Three days is too little (the "weekend" is too long), but four days is just right. I've worked four days for years, now I'm temporarily working five, and I am looking forward to going back. Two days aren't long enough to unwind from the other five, I keep feeling that the week is too long and the weekend too short.
Working four day weeks, every week I'd think "damn, is it the Thursday already?" and on Sunday I'd be looking forward to going to work on Monday
I always feel like I need at least one day to unwind and recover from working hard all week. But then it's Sunday and I need to get ready for the next week already. Would be great to have one day to not be recovering or preparing for the next work week.
Working four day weeks, every week I'd think "damn, is it the Thursday already?" and on Sunday I'd be looking forward to going to work on Monday