All of Irwin Allen's shows had this in common.
Whether it was;
Voyage to the bottom of the sea
Lost in Space
Land of the Giants or
Time tunnel,
all these shows had alternating episodes that ranged from the sublime to the ridiculous. An episode that was epic and thought provoking would be immediately followed by an absurd but still imaginative episode.
Can you list off any that went from an epic episode to be followed by an absurd one or vice versa?