I just stopped reading a book - The Orpheus Trail, a mystery by Maureen Duffy- because it employed a plot device I HATE. The hero, an historian/ director of a small local museum, has lots of information about a series of gruesome murders. He does not go to the police with this information on the weak excuse that he "doesn't have enough information" to go to them. Instead, he investigates the crime himself. This is despite the fact that the police repeatedly ask him for help AND the information he is withholding is clearly relevant to the case- he is receiving threatening letters, his cat has been kidnapped, and he has seen the last person one of the victims spoke to (whom he hasn't mentioned to the police), doing some suspicious things.
I don't very often stop reading because I am annoyed at the writer, but I just did. This had all the ingredients of a book I could have liked a lot, but the stupid plot device of the hero putting himself in danger because he doesn't go to the police is just laziness on the writer's part.
This plot device in mysteries is similar to the plot device in romances where the entire plot is a result of two people not talking about something that normal people would talk about and that would take about 2 minutes to clear up. Instead, there are 200 pages of angst because they don't talk.
I can't stand those either.