Strong visual effects can be the difference between a stunning visual experience and an unintentional laugh-fest like The Scorpion King. In some cases, that bad CGI is to be expected: in actual fact, it used to be part of Doctor Who's real charm and some more cheaply made films can get by on similarly cheeky effects.
But there's also no getting around the fact that big money movies have something of a responsibility to protect their most iconic characters. And when those characters have built up a legendary status, whether from a previous film or the source material, any sudden betrayal by a rushed effects team trying to digitally remove a moustache ends up feeling even more sore.
Superman's no the only example and he's far from the most beloved of characters to be undone by bad CGI either...
10. Agent Smith - The Matrix Sequels
While Neo was the Chosen One and Morpheus and Trinity were both legitimate bad-asses, make no mistake that the biggest stand-out character in The Matrix was Hugo Weaving's Agent Smith. His clipped pronunciation, creepy, government stooge get-up and faintly alien aesthetic made him one of the most recognisable villains of the movie century so far.
The Wachowskis, clearlyaware they'd struck gold with Weaving's nefarious agent, brought him back for the sequels, dialled up his duties and gave Weaving even more licence to perform. He added thick slices of ham, but Agent Smith's mythology grew with it and were it not for the unfortunate curve of the VFX graph, he would have been one of the few umblemished things about the Matrix sequels.
Sadly tough, as Weavings' performance got better, the effects got increasingly worse as the directors sought more spectacular set-pieces and the result was a human performance let down horribly by ragdoll physics and awful CG rendering that made him a bit of a laughing stock.