Galatea

If there's a more convincing NPC in all of interactive fiction, I've yet to come across her. (I do dearly wish that Emily's updated Versu version in which one can play as Galatea had been made available.) Conversations don't get more plausible than this in a parser format.

It's also worth noting that, along with Aisle, this game introduced me to the peculiar strength of multiple endings in IF - that it's a format in which one needn't assume that any particular reading of the text is the correct one (let's face it, your average Choose Your Own Adventure has a great many bad endings, and tends to implicitly prioritise *winning* ones). This is a delicious storytelling technique for anyone even the slightest bit intrigued by metafiction, and I'm surprised it isn't used more often. Well-written to boot - a joy to play with.