According to unverifiable sources, the key to a happy Monday is ignoring all emails.
For those who want to take it to the next level:
Learn to use the undo button as a weapon
Develop your own email filter bubble
Connect with fellow prophets of doom:
Join the Monday Blues Cure club
Monday Blues Cures Support Group
Disclaimer: Not responsible for actual cures.
Disclaimer: May cause actual Mondays to still be terrible.