9. John Connor - Terminator
The First Time
John Connor is one of the most statuesque and unforgettable characters in all of sci-fi fiction, the leader of the human resistance on which the future of civilisation depends.
And when Christian Bale was cast to play the part in 2009's Terminator Salvation, fans were overjoyed. After the fairly divisive response to Nick Stahl's rendition of the character in Terminator 3, a talent like Bale seemed like a significant upgrade.
A shock it was, then, that Bale gave an oddly flat performance in the role - all shouting and no feeling. The bunk material didn't help, but Bale later admitted that he regretted taking the part and only did so out of spite after people told him he shouldn't.
The Second Time
If Bale's performance was boring and soulless, he at least didn't totally derail the integrity of the character in the way that the most recent sequel Terminator Genisys did.
The criminally underrated Jason Clarke was cast in the role, yet this fine choice was upended by the film's ballsy yet misguided dramatic gamble, to transform Connor into a villain.
The resistance leader is compromised by a T-5000 (Matt Smith) early in the film, turning him into a human-nanomachine hybrid Terminator known as the T-3000.
Again, it was a bold storytelling decision, but not one that remotely benefited the character or the franchise. Poor Clarke was given so little to do here, and when he was destroyed at the end of the movie, fans felt nothing (apart from rage, perhaps).
Connor will be briefly featured in the upcoming sixth film, Terminator: Dark Fate, though it's said to be a minor cameo, and if rumours are to be believed, his origin story will be tinkered with yet again. Oof.