This is a surprisingly difficult question for me. They were each probably many years ago.

My best day. May 17, 2003. My wedding day.
My worst day. August 9, 2019. The day my beloved wife died.

Best day started 7am 11th July 2002, when I moved into the kennels and cattery I still
Worst day .. when my friend died in my arms and the ensuing capture

Best day? Any day of our Fort Pickens FL vacations. Pristine white beaches, body surfing, seafood, bike rides...

Worst? The morning that I told my young children that their father had passed away during the night.

The best say ever was when I made out with Chris Hemsworth.

Which also happened to be the worst day, when I woke up to realize it was just a dream.