Lost in Space is unwatchable as an adult.
There are so many shows that we enjoyed 50 years ago that we look back on now and say ‘how did we watch that then?’.
I think part of it is that TV was still new in the 60’s and color TV was just making the scene. So part of it was just seeing anything coming from the tube.
I think another aspect was that shows came out weekly so you couldn’t binge. With a week between episodes, you didnt see how repetitive a show could become in a short period. When you binge a whole season in two or three evenings, the shallowness of the plots becomes more evident.
Finally, we enjoyed TV shows more then because they were family shared experiences. Mom, Dad, and kids all sat down together for their favorite weekly show and you probably only had one TV between all of you. Today, everyone can just go watch their own thing in the privacy of their own room and never interact with family or friends. No social aspect to it.