Films are complex beasts with so many moving parts that mistakes are unavoidable. Even the blockbusters with the biggest budgets and most sets of eyes on them routinely make it to cinemas with a few errors, especially when it comes to continuity.
From fluffed lines to errant extras, numerous mistakes have to be corrected on set (or, increasingly, in the editing suite) but occasionally they can bring a new and welcome quality to a scene.
