Kerchak's face when he sees Tarzan has brought humans
It's a small detail about the movie that I like.
When Kerchak comes back and sees Tarzan has brought humans (Jane, Professor and Clayton), one small detail I like is that Kerchack doesn't attack Clayton or any of the humans right off the bat. He probably would've anyway, but it wasn't until Clayton aimed his gun at the gorilla and that's what sent Kerchak into rage.
Before that, Kerchak looked very confused and hurt. Like he couldn't believe Tarzan would bring humans after being told not to.