8. The Randomly Changing Conversation - Unfriended
Given that Unfriended takes place entirely on a computer screen, much of its imagery was generated in post-production and could therefore be easily tweaked, making it far easier to believe that this bizarre mistake was discovered and simply left in to mess with viewers.
About 10 minutes into the movie, Blaire (Shelley Hennig) asks her boyfriend Mitch (Moses Storm) why he isn't answering her, and after he explains that he got a message purporting to be from her dead childhood friend Laura Barnes, Blaire replies, "That's not funny." Mitch fires back, "I'm serious."
However a few minutes later we see the same chat window again and the last two messages are now gone, replaced with a rather different exchange. Blaire now says, "Yeah I think someone hacked her account," to which Mitch replies, "Maybe."
Much like American Psycho, we'll likely never know for 100% sure if this was a genuine screw-up or not, but either way it creates an eerie vibe, that the ghost of Laura is screwing with Blaire and Mitch from the jump.