Jessie and James are in love with one another, they're just those type of people that don't realize it.
May, Drew, Zoey and Dawn are Grand Coordinators now, Paul won a League, and Gary is the world's youngest regional professor..... we'll never see them again so.... best explanation
Ash's dad is a bum named Red who left Delia before Ash was born, utterly failed at his dreams, and went to the entire opposite end of the world to run away from his failures. TLDR; Ash's dad is a bad man, which is why Oak and Delia never talk about him
Butch/Cassidy have done what the TRio failed to do, they made a successful Sinnoh Team Rocket branch and are in charge of day to day operations. An excuse as to why they were never seen again
Persian actually doesn't like Giovanni, he only sticks around to piss off Meowth
Pierce and Tobias are brothers
The SM pirates stole Team Rocket's BW sub and made changes to it
All the movies up to Victini are canon. Victini onwards are not, they're just alternate universes not so different from the one we're familiar with.
Ash may or may not have multiple personality disorder. Explaining his inconsistent personality from saga to saga, and why he doesn't remember certain Pokemon he should
Cilan actually is a connoisseur at everything, he's not over exaggerating. He's extremely talented and only messes up to not make others feel bad about themselves.
Serena moved on, if she truly still loved Ash don't you think she'd have returned by now?
Despite what countless characters and Pokemon say, Ash is
not the chosen one. He's destined to guide the
true chosen one to save the world from a threat unlike those he's dealt with before. Until he meets that person, he's cursed to lose every official Pokemon League he competes in so he continually travels