Harry Morgan, the actor cast to play Officer Gannon, stood only 5'6", and would have failed the height requirement for LAPD officers at that time.
Recurring: when Gannon and Friday are listening to someone, they often both nod repeatedly, they even will look at each other and shake their heads no in unison. It looks odd---a bit reminiscent of the Muppets, when those close their mouths as they are agreeing to something. Meaning, there is no character life---no thinking process behind their action---to back up their constant nodding; they simply nod or shake their heads no because the script calls for it and it looks contrived, and the actors stiff and unnatural.