Best accidental bonus in a movie or tv show?

[Deja Q]

Due to circumstances during a production of a tv show or movie, changes had to be made.

Name a change that benefitted the tv show or movie?

In "Star Trek Generations", they had to use the TV sets as they would not build new ones. As a result, they turned off most of the interior lights and let the outside sunlight shine in. The result, unintentional, is pretty damn impressive. Oopsie-doodles, but so much the better for it. Until now I thought only black and white photography had such depth and character with shadows. "Generations" easily does a one-up... but it was by accident; to hide the fact the sets were nearly 8 years old and any speckle would easily be seen on the big screen.

In the Doctor Who story "The Greatest Show in the Galaxy", an asbestos scare in the BBC studio forced everyone to film the story outside. They raised an actual tent. The result looked more realistic - even if it was entirely a coincidence. Oopsie-doodles.