I finally figured out why.
When I was a kid (in the long-ago 1960s) I had a strange home life. There was lots of love there, but my Mom suffered from paranoid schizophrenia and depression, and in those days people were less understanding about these things. We were the neighborhood outcasts, and some of the other kids made fun of my Mom. (I fought back, though.) Plus, I was a creative kid, and that didn’t fly with the strait-laced, Roman Catholic families on the block. I had moments of great joy as a kid, but when I was sad, it really floored me. I played hooky from school a lot.
I found comfort in music, and I especially loved watching the Monkees TV show. On one of the episodes “Monkees at the Circus”, the boys try to cheer up the circus owner’s daughter, who is sad cause the circus may go out of business. In one of the show’s romps, the boys dress up as clowns and try to cheer her up. I saw this romp a few days ago for the first time in decades. I remembered that when I first watched it as a kid, I imagined that the boys were trying to cheer me up with their clown act.
Now I know why Sometime in the Morning always pops into my head when I’m really depressed. And it always cheers me up - no visits to the therapist needed here. The Monkees music works just fine.