The whole point of this scene was that the star wasn't typically scary, but that its size was preposterous and grotesque, and that made the Stay Puft man an oddly enduring image of the Ghostbusters films (even more so than any of the villains in the sequel.) But when the curtain drops a little and you get a shot like this that shows the magic behind the sequence, it loses something of its appeal.
9. Harry Potter: The Deathly Hallows Part 2
He might not yet be as universally cherished as the likes of Darth Vader or Hannibal Lecter or Frank Booth, but Ralph Fiennes excellent portrayal of Voldemort in the Harry Potter films deserves to be as heralded. And a simple thing like the lack of a nose did major things for the impact of the character - as did his unfalteringly terrifying demeanour. So the sight of Fiennes slipping out of character while still in make-up for an impromptu "wassup" moment, with his nose not yet CGIed out, is a touch disappointing. Voldemort's power is in his altered humanity, and with a nose, it's all too easy to just think of him as a little bit unhinged.