5. James Cameron - Titanic
The Plot Hole: Why couldn't Jack (Leonardo DiCaprio) and Rose (Kate Winslet) both fit on that damn door? Jack's death was for nothing!
This much-discussed plot hole was brought back into the spotlight in a 2012 episode of MythBusters, where hosts Adam Savage and Jamie Hyneman determined that, by tying Rose's life jacket underneath the door for additional buoyancy, the door would've stayed afloat with both of them atop it.
Granted, you can argue that you're not going to be at your most logical with hypothermia about to set in, but even so, writer-director James Cameron himself appeared on the MythBusters episode and begrudgingly admitted his fault.
He said, "Maybe we screwed up and the board should have been a tiny bit smaller", but prefaced this by saying, "I think you guys are missing the point here. The script says he dies, so he has to die."
In a more recent interview, Cameron seemed to distance himself from ever copping to the plot hole, saying, "They’re fun guys and I loved doing that show with them, but they’re full of s***."