These days the average movie contains around 1250 shots, going up to 3000 for high-end blockbuster movies, representing literally thousands of opportunities for filmmakers to sneak sly nods, references and minor details into their movies that 99.8% of viewers will absolutely miss.
But one of the many joys of online film discourse is the absurd lengths which fans will go to uncover secret messages, symbols and gags hidden in their favourite films, such that these details don't tend to remain a secret for too long.
Thanks to fiercely committed online communities like /r/MovieDetails, there's always an army of film buffs keen to dissect a film shot-by-shot and even frame-by-frame, unfurling every last secret the filmmakers sneaked in there.
For each of these 10 movies, there's no doubt that every single one of us missed this ingenious hidden gag on a first viewing - and perhaps on subsequent ones, too.
But once you know these whip-smart, hilarious and straight-up awesome details are in play, you'll never be able to watch the movies quite the same way again...