Parley Baer: Great Character Actor

Many if not most actors carry their external "I'm acting" personas with them. They get type-cast for a reason.

Those actors still retain the ability to be wonderful actors, especially the ones who can use the external persona to good effect. 

Parley Baer is one such example. He is excellent as characters who are somewhat loosely-moraled, slightly whining, constantly bargaining and kowtowing. In Perry Mason, this character type is often a villain--and creates havoc for others. In Andy Griffith, as the mayor, Baer is simply the resident politician. Alongside his complaints--some justified (he was right about the band!), some not--he is also superbly comedic.

The interesting point here is that Baer knew how to shift from the more villainous aspect of his external persona to the sweeter aspect. Not all actors can. Anthony Head, RIP, was fantastic as Giles. But he only seemed to know how to play one type of villain, so his evil headmaster on Doctor Who was not much different from his version of the self-centered Adam Klaus which was not all that different from the vain Sir Walter Elliot in Persuasion.

Wonderful actor--but surprisingly less versatile in tone. If he was cast correctly...

I suspect casting directors never get enough credit.