Why was Blue so 'slow?'
When I was a kid, I thought he was slightly mentally "challenged." I wondered if he had a difficult birth or something, and that's why he was always so emotional and so slow on the uptake. I remember that there were several other young men on TV who were dumb or slightly handicapped in some way during the late 60s TV era: Peter Tork on "The Monkees" and Bobby Sherman on "Here Come the Brides," for example. Maybe it was a trend that appealed to teenyboppers of the time.
I always felt sorry for Blue and wished he could have been as smart as his dad. Like I felt sorry for "Fredo" from "The Godfather."