Make people expect something obvious, then at the last minute, do something completely different.
The surprise factor at play here is what’s so interesting. It can be impressive and even funny, if the situation asks for it.
You may also use the narrator trick, who gives the reader the impression that they know something more than the characters. But with the sudden twist in the story, the reader is tricked and therefore gets a kick out the realization.
It is a good technique to use for any creative outlet. Point left and shoot right.