The way my class schedule works out, most of my class time is MWF. Tuesday’s technically longer, but more spread out. Thursday is the second easiest day, and Friday is the first. Monday and Wednesday are identical.
So why is Wednesday the Worst? Because on Monday one is somewhat refreshed from the weekend, or at least they’ve gotten a little more sleep. Wednesday, however, is right in the middle. You’ve already suffered through two days, and you have another two after.
I think we could all use a mid- week nap.