Armorshipping. I loved Serena's character in the games (more so as your rival, obviously), so when she was being announced as one of Ash's companions, I thought it'd be interesting. Everyone wanted to say this was it, this was THE female companion that would make Ash suddenly realize he wasn't entirely asexual.
Instead, I cannot stand Anime!Serena at all. She's essentially there to be a love interest. She has very little personality, and little to nothing in common with the personality of her game self. The fact that she was just SHOVED into Ash's back story pisses me off to no end. She's like a badly disguised Mary Sue: she just shows up and goes 'DO YOU REMEMBER ME', and suddenly she was part of his childhood and he's never mentioned her before because...no specific reason, just 'didn't remember'. Yeah, all right.
I'm really, REALLY hoping they don't make the mistake of making it cannon. I want to like this pairing, but it just makes my blood boil whenever I see it/hear about it.