5. Terminator Salvation
The various versions of The Terminator make it deviously hard to get a lid on what rules of time travel were dealing with. The first was dealing with closed loop/grandfather paradox (something that isn't as hard to understand as people would have you believe), but the second introduced alternate timelines and the third combined the two to create a changeable, but over-ridingly destiny ruled concept. What Terminator Salvation did, however, was plain ridiculous. Directed by McG, a Michael Bay for those who cant deal with more than two syllables, the film attempted to introduce a new concept, despite all the sensical ones being used up. Instead, what we got was a film that thought it was changing everything when it wasn't. Early on in the film Christian Bales John Connor discovers early plans for the T-800 he loved so much and ends up fighting one in the films finale. As Salvation's set in 2018, this is a good decade before theyre meant to be created, throwing off the timeline just to have a young star as Conner. Quite what element of Salvation is the worst offender is hard to say; having John Conner as an Anakin Skywalker style underling rather than a brave leader or completely screwing with the pre-existing rules without doing something interesting. Maybe McG would have expanded upon these for his planned trilogy, but either way, we weren't happy.