Mum and I finished Sherlock last night. I also explained slash to her. She was confused. She's so cute when she watches TV, though.
[Reichenbach Fall spoilers]
John (on screen): My best friend, Sherlock Holmes, is dead.
Mum: What?! *matter-of-factly* That can't be right. He must be mistaken.
After John tells off Mycroft:
Mum: That Mycroft is such a bastard!
After the episode:
Mum: *very small, hopeful voice* Do we have Season Three?
I still find I get very tense watching the episode, even though I know what's going to happen. I suppose that's a sign of good teevees.