Fantasy Island was a Genre Show, and often had More plots going than just different ones for the Guest stars. IE: Often a Plot of Tattoo being given an important Fantasy to oversee being granted, or A Maid finding Love or Mr. Roarke showing a Dark or mysterious side, etc (Though, Dark Roarke was far more directly shown with the Malcolm McDowell Remake)
The Love Boat also had a Ship's Crew Plotline, along with the Guest plotlines, which often developed the Crew's Characters.
And those started a Decade + earlier
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?