There's a hysterical blooper that can probably be found on youtube during the filming of a documentary by the Sci-Fi ("SyFy" - yuck) Network to celebrate, I believe the 25th anniversary of LIS. Bill Mumy was talking with the Robot who made disparaging remarks about Dr. Smith and Jonathan Harris entered the scene, in character as Dr. Smith, arguing with the Robot. He pulled out the power pack and the Robot dropped its arms, but even something more: the claws fell off. Both Mumy and Harris first had shocked expressions, but when the stage hands in the background broke into laughter, Harris said, using a really funny British accent: "His f*ck*ng hands fell off!" Mumy almost collapsed in laughter.
In the OS, the role of Dr. (also Colonel) Smith was to have him as a totally evil persona. His character was added (along with the Robot - neither were in the original pilot) was added to create "tension" among the other characters to flesh them out. (The pilot, which was only one hour long, was expanded through the first four episodes with newly shot scenes, including Dr. Smith and the Robot, interspersed throughout.) After several attempts at killing the family, he was suppose to be killed off. But Harris knew what side his bread was buttered - he had a good job, was actually paid more per episode than the other performers (because he was a "special guest star") and began to "lighten" the character to make him more palatable to children. It worked; CBS kept him on and the lovable buffoon evolved. LIS was originally designed as a hardcore science fiction adventure of a family trying to survive. CBS picked it up instead of Star Trek, having first option. It transitioned from being a serious sci-fi series to a neo-comedic fun fantasy. By the second season, it also had to compete against the highly popular goofball Batman airing at the same time. All seriousness was jettisoned, and instead we had the green-skinned Lorelei seducing Smith, intergalactic department store vending machines, knights in shining armor fighting dragons, and talking vegetables. Some of the first season episodes were brilliant, including "My Friend, Mr. Nobody" and "Invaders from the Fifth Dimension." The writing, direction, acting was remarkable. But there were moments in the other two seasons. One of my favorite lines came from Dr. Smith when he realized that he has ruined young Will's belief in magic: "Dear, dear William. Don't be in such a hurry to grow up. It's really not all that worth it."
A re-imagining of LIS would be interesting if it's decided to keep Smith as a total villain.
Gerard