Curse you “Fight Club.”
You were a great movie, but you have forever changed the way I watch movies in the theater. Thanks to your sequence on the “cigarette burns” that projectionists put on film to remind them to change the reels at strategic amounts of time, I can never watch a movie without using them to judge how much time has gone by.
Which also means I can judge about how much time is left. And I hate being conscious of time while watching a movie, although I often force myself into being in such a state.
Marshall and the Movies 
Does it really happen in real movies? I never noticed!
Not in movies projected digitally, but they are very present on film projectors. Look every twenty minutes or so in the top right corner of the screen.