Trevor and Musgrave
I know I’m biased and I’ve said this before but if you don’t have much familiarity with canon and you’ve never done it, go read The Adventure of The Gloria Scott and The Musgrave Ritual as a double bill and just look at how Doyle writes the descriptions of Trevor and Musgrave. The set up for the two stories are quite similar and then head of in different directions - neither case had Watson in them but they are both about storytelling. Both openers are a joy. Because Sherlock is weaving a story from his past for Watson’s and his entertainment.
Musgrave gives a lot more than TGS does and its characterization so queer coded. Victorian queer euphemisms crammed in line after line to describe the client. And the mirror of Sherlock telling John the story of how a Musgrave sat and told him the story is one of the best narrative “nests” in canon. Watson is *captivated*. It’s just so well crafted. And captures something so beautifully intimate about the two of them by the fireside in 221b.
Both rank very high for me in canon. Highly recommended. And it’s never too late to start reading ACD.