To go forwards, sometimes you need to think backwards
Good detective work is a highly creative process and requires a different way of thinking.
"It is a capital mistake to theorise before one has adequate data"
– Sir Arthur Conan Doyle, A Scandal in Bohemia.
I still reread the Sherlock Holmes corpus every year or so. You would assume that any detective fiction would lose its appeal once you know whodunnit. These stories are rather different, however: for amateur detectives (and professional marketers) they are a useful lesson in how to think.
The genius of Sherlock Holmes is often misrepresented. He is liable to be depicted as a model of pure rationality: a simple logician, or a kind of human calculating machine. But it is obvious to any sane reader that he is nothing so dull. It is Lestrade who attempts to solve crimes through plodding sequential logic. Holmes's genius is of a highly creative kind.