What are your absolute favourite episodes
For me the finest one is the Patrick McGoohan/Leslie Nielsen one, Identity Crisis. Maybe it's the use of Madame Butterfly but I love this character. Geronimo! and his speaking his servant's native language. And Leslie's hilarity at the cigarette machine. And so much more.
Almost tied with this is Swan Song, with Johnny Cash. Anyone who sings like that cannot be all bad, as Columbo said. The parachute thing - not an overdone plot device. This had true suspense plus the amazing Johnny Cash as a sympathetic villain.
Close to these are William Shatner's and Robert Culp's episodes - all of them, because they are just such hilarious, over the top, magnificent, egotistical villains.
Yes I also appreciate many, many others but these stand out for me.