TNG in particular did a great job of stretching the characters by building them up to a definitive version and then showing us, in one way or another, a variant or situation that completely shatters that image. Data and Lore. Alternate Riker. Broken Picard. Troi and Lwaxana. Worf and also Worf but later.
I was going to say Worf and Alexander but then I realized that it’s really Worf becoming a dad that shows us the transformed Worf.