I quite liked The Thirteen Problems, they are 13 short stories where a group of people tell a whodunit, at the end of the story the other guests have to work out who did it and how. The reason why I liked the short story collections is because I quite liked how Miss Marple trounced the all!!!
Your Post explains just what Agatha Christie's Books and this site is about, I don't find Sleeping Murder Scary at all but I find your description fascinating, I love 4.50 From Paddington in fact for me they tie in 1st place with A Murder Is Announced, Paddington Is just a Cracking Good read, It has this cozy Atmosphere, wonderful Characters and a very Comfortable feeling which sucks you in and takes you off your Guard.
I agree I have learnt a lot from Agatha Christie, on subjects like Geography, History, Mythology, Shakespeare, Literature and not to take things at face value.
I think I must like the more rural books more than others because At Bertram's Hotel Isn't in my top 3 but nor is it in my bottom 2 because it has Rich Characters and the Plot is like most of Christies work Wonderful.
Sleeping Murder and A Murder is Announced have always been my favourite Agatha Christie Miss Marple novels.
My favourites are A Murder is Announced and The Body in the Library. I love the murders that take place when the murderer is apparently somewhere else.