Sarek

I think it's impressive enough that a respected character was borough onto TNG as a bridge to the Original Series, but the execution thereof just raises it to a whole different level. Sarek is losing control of his emotions on the eve of his crowning diplomatic achievement - which is shattering to a Vulcan and an interesting way to see the effects of dementia. Picard says it best: "It's ironic, isn't it? All this magnificent technology, and we still find ourselves susceptible to the ravages of old age" But it's also Picard who ends up coming through in the end, and the scenes with Stewart and Lenard are both powerful and heartbreaking.

Honestly, before watching this, I'd just expected to see Sarek show up as little more than a nod, like DeForest Kelley in 'Encounter at Farpoint'.

But this was a surprisingly considerate story.

9/10