Theres a seedy underbelly to the world of film trivia. Head over to IMDb and you can find as many little factoids about any given film as your brain can hold, but those sections only scratch the surface of what filmmakers stuff into their works. We all know about the little ticks each director has. It makes going to see their films a little more exciting; hoping to spot the in-joke without having to Google it afterwards. Where will A-113 pop up in the latest Pixar movie? Wheres Alfred Hitchcock going to be lurking in the background this time? How will Peter Jackson turn this wonderful source material into an overblown CGI extravaganza? All fun Easter Eggs you grow to expect, but they're more than a little pedestrian. You see alongside the famous tricks even the most film illiterate viewer could pick up, theres a plethora of deeply hidden traits that run through their work. Not readily available on the commercial sites, theres a black market of increasingly obscure elements in your favourite films. From dangerous message boards to diverted comment sections, there's more trivia than you suspect hidden away. Busting open this hidden world, bringing these dark secrets into the light, we present you with eight great directors who, throughout their careers, have had a recurring trait so specific you wouldn't believe it unless it weren't on the screen in front of you. These are traits I've spotted over the years slowly watching the directors back catalogue. Some have been helped by outside influences, but most I've gradually discovered from arguably too many hours scrutinising my DVD collection. Some may not be as hidden as others, but all show our favourite directors have a relatively obsessive streak to them.