It wasn't hard to see who Sherlock had on his mind with his comments about women having short hair too, and Mary's (especially in the style she has at dinner, pinned back into little waves) is absolutely gorgeous to me, so I'd love to see some fic about it! It can be relatively chaste admiration, one or both of them perving about her hair really hard and touching it/disheveling it, or a bit of both. (I'd also love a little gender/identity play with how it slightly resembles John's hair, though I'd prefer if that didn't go into Sherlock thinking of them as truly interchangeable.)