I watched a bunch of those eps out of curiosity, mostly on the internet. The robot was, by far, my favorite character. I literally LOL at the things he (*) said & did, especially to Dr. Smith. I'm not sure I could've stood watching too many eps if it hadn't been for the Robot. (*I say he, because he did fall for a female robot once...just another thing that cracked me up.)
Granted, Dr. Smith, especially as the show got progressively more silly, was also hilarious. In real life, I wouldn't tolerate him at all (**), but on the show, his choice of words & delivery were cheesetastic awesome.
(**In the 1998 movie, where John Robinson tells Maureen that Smith is dangerous and maybe he shouldn't have let him live, I instantly imagined myself in Maureen's place explaining, "Don't worry about it, he's already in deep freeze. If we make it back to Earth, we turn him over to the authorities. If our provisions run low, he's on the menu.")