12 Dumbest Decisions In Harry Potter Movies

2. Harry Trusting TWO Mysterious Books

What is it they say about fool me once?

In The Chamber Of Secrets, Harry ignores the fact that he spent most of his first year under the threat of mysterious death and then confirmed that Voldemort wasn't completely gone by making friends with a suspicious book that talks to him in secret. Nothing at all ominous about that, is there, Harry?

Naturally, it nearly kills him and his lack of suspicions almost kills Hermione, Ginny and several others. All because he didn't think to report it to anyone.

And then, because Harry learns precious few lessons at all, when he's presented with another book that seems to be transmitting helpful, mysterious messages to him, he just trusts that it will be fine and not at all linked to Dark Magic. So trusting is he this time that he uses Sectumsempra without knowing what it does and almost kills Malfoy. Shame on him, right?