9. Jimmy Olsen
This is a bit of an unusual one, because Smallville's version of Jimmy Olsen was pretty comic-accurate, too. He was socially-awkward, unintentionally funny, and yet very lovable all at the same time. It's what makes Jimmy, well, Jimmy. And yet fans are a bit divided over the adaptation.
Aaron Ashmore was brilliant in the role, nailing all of Jimmy Olsen's nerdy intricacies to perfection. However, fans weren't necessarily fond of some of the storylines he was involved in, particularly his early-on jealousy of Clark, his on-again/off-again relationship with Chloe Sullivan, and the unique relationship he had with Kara.
Look, Jimmy Olsen was literally created to be a supporting character and that's exactly what he is in Smallville, but it often felt like he was just there to get involved in - or react to - other people's storylines. He didn't have much that was his, and that made him get lost on the show quite a bit throughout his three-season run. And then there was the decision to kill him off right as he found his footing, only to reveal that his little brother was actually the real Jimmy Olsen.
A decade later and there is still no making sense of that storyline.