It goes without saying that the hero of a movie is supposed to be the one you want to win the most. They're supposed to be able to capture the hearts and minds of the audience so that there can be no doubt that they're the ones we want to beat the villain. That's particularly got to be the case when the villains are interesting too.
Unfortunately, sometimes heroes can't be as interesting as they need to be (hence the rise in the trend of villains stealing the show in way too many movies) and it's actually far more minor characters who end up being the real stars of the show. That's got to hurt when you're supposed to be the biggest deal.
Sometimes film-makers just can't help but upstage their own main characters...
13. Korg & Miek - Thor: Ragnarok
It's fair to say that the third Thor film did a lot to reinvent the God Of Thunder. Thor: The Dark World had driven him way too far into the realms of grim seriousness and he was in danger of being relegated to an Avengers character only. But then Taika Waititi came in and injected some of his own brand of comedy and all of a sudden Thor was being talked about as a possible lead character for Phase 4 of the MCU.
That said, it wasn't Chris Hemsworth's hero that stole the show in Ragnarok. He was in danger of being upstaged by both Valkyrie and the Hulk for lots of the film, but it was two characters with significantly less screentime that got the real MVP labels.
Waititi might have been a little restricted in his creativity because of the MCU's guidelines, but in Korg the Kronan he was most able to express his own sense of humour and it showed. The rocky alien was a brilliant addition to the Thor franchise and if he and silent sidekick Miek don't get a spin-off, it will be a travesty.