They jammed in a freaking elf and dwarf love interest angle somewhere in the movies.
In the entire Middle-Earth Legendarium, Elves and Dwarves were bitter rivals to eachother to the point where the idea of A elf and A dwarf would never work together in a conceivable fashion that constitutes a relationship to that extent. Legolas and Gimli I was okay with because they developed as functioning partners for the sake of the Fellowship when the call was heeded.
But what happened in the Hobbit, was once again a shining example as to how stupidly obsessed Hollywood is, with cramming romance into everything.