In The Fugitive, when Dr. Kimble jumps off the dam, it’s so obviously a dummy that it takes me out of the scene. Great movie otherwise.
What really throws me out of a good movie is when I cringe in embarassment at something they have done in the film. I have to say that the ringwraith coming running towards the audience with a torch stuck in the front of his hood was mortifying. I nearly died of embarassment at how tacky it was (looked like a Scream 83 extra had wandered on-set). Took me a minute or two to get back into the film at that point.
Doh, sorry, talking about LotR film of course, Tiburon reminded me of it.