I have watched this twice in the last two days and it just keeps getting better....
The more this is watched, the more humourous subtleties are recognized.
From Don Knotts' spastic actions after getting out of his car to the hidden laughing going on (check out the one detective when it is being debated whether Sid Ceasar and his wife should be helped out of the hardware store - the one on the left keeps breaking out of character and laughs).....