The characters I hate the most in fiction are the really neat people. People so interesting, cool, intelligent, even adorably quirky that they would be the grand prize of any dinner party.
Besides Sherlock Holmes, and the usual cast of others, one character who comes to mind is Campbell Alexander, the really neat guy who's the lawyer in My Sister's Keeper by Jodi Picoult.
Really neat people don't exist. They have their moments that make them not so neat, but that's left out when selling books.