Sherlock, let's leave it at The Final Problem

As the curtain came down on another Sherlock series, I had mixed feelings on how the season four finale came to its conclusion and switched the television off with one overriding feeling: I hope this is the last episode they make.

[a serious amount of Sherlock cross-season spoilers to follow, so if you haven't seen any of it but want to, do not read this post; you have been warned]