Written and arranged by Brian to be sort of a Guess I'm Dumb part two, which was a song he wrote for GC in the early 60's.
These two had a tremendous amount of respect for each other throughout their careers. Most know that Glen toured w/ the Beach Boys in place of Brian for a year.
I get the love for Cash's Hurt, but this from GC tops it imo.
As I always say - help out a friend or a relative or a neighbor who needs a few hour break from caring for an ALZ loved one. It's the best thing you can do.