Jared Leto. Fucking hate him, I hate every single singer which decides to "turn into" an actor. But mostly Jared.
Jared Leto was already a really successful actor long before his music career took off. Plus a lot of his movies are great and he's great as a supporting actor; Requiem for a Dream, Fight Club, American Psycho, Panic Room, Lord of War, Chapter 27, Mr. Nobody and Dallas Buyers Club. He always gets shit on because every one thinks he's a frontman turned actor when it's the other way around.