I really enjoyed this new episode of Sherlock.
In particular, I loved Mary as spy/agent/infiltrator. I could have watched the Mary as Spy show, but unfortunately, they had her leap in front of Sherlock.
The mastermind behind everything was a complete surprise. I was hoping it wasn't Moriarty, because I never liked this show's particular Moriarty version and am hoping he remains dead.
John is being completely unreasonable, and I also don't feel for him as I might since he was having a flirtation with some woman on the bus. Unworthy, John, completely unworthy of Great Mary The Spy and you haven't any leg to stand on being angry at Sherlock.
I suppose it's some form of Make Up/Break Up between he and Holmes, but meh.
Red Herring city, I thought The Black Pearl was surely in one of the Thatcher heads, but no.
I thought the scene where they show Mary's old agent bud hiding the flash drive in the statue head was silly, he doesn't get it in there and seal it, he just has time to tip the bottom, stuff in the drive and tip it back. The first person to handle it would have seen it and there would be no head Thatcher plaster heads smashed at all.
Mycroft's office was pretty creepy, more like a jail cell than an office.
I liked Sherlock's patience with the dog.