Saturday - obvious choice, high point of weekend. You know you have that night/next day to sleep if you have to. UFC cards help this day as well.
Friday - Slack day at work, if I work at all as I get Fridays off sometimes (God I love 4 day x 10 hour work weeks when they come around)
Thursday - Sometimes it's my "Friday", sometimes it's the "almost end of the week day". Plus NBA double header night!
Monday - Like the OP, Mondays are easy for me. Talk about your weekend with co workers, enjoy stories, kill some of the day. Usually you're well rested/you could also play the "sick all weekend" card to escape without having to set it up all day at work the day before.
Wednesday - Sometimes it's my "Thursday" (Like today) and it's almost the end of the week. By now you're semi used to being tired for the week.
Sunday - I don't like this day. Besides NFL, it's the day where you just know work is around the corner. You enjoy yourself a bit, but you know work is looming.
Tuesday - Worst day. You have trouble falling asleep on Monday night because you're not quite tired yet, and you pay in the morning. Then it's not even close to the end of the week yet and you know you have 3 (or 2) days left.
Just my take