I used to take my flex day (that's what we call it) on Fridays, but switching it to Mondays was a game changer. I'll never go back. Like some have stated above, the primary benefits to having Monday off:
1. Most other people are at work/school, meaning your errands, appointments, and hobbies feel much less obstructed. Jogging, waiting at the DMV, going to the bank, going out to eat, you name it, the lines and traffic are always lighter.
2. Fridays are usually pretty relaxed at most jobs anyway ("
Casual Friday"), so you may as well work it.
3. Nothing beats waking up Monday morning and sipping some hot coffee on the front porch while you watch the masses scurry around. Smug-factor at 9000.
Of course, I'm talking from the perspective of an office job. When I worked sales, Friday and Saturday are when I made the most money, so my answer would change based on that. I have never worked food service, but I would imagine that if you work a tip-based job, those would be the days/nights to work as well.