The Montagues and Capulets never carried a real reason to feud. The families simply hated each other. Had one lived outside of the same region of Italy, chances are each side wouldn’t have even known of the other side’s existence. Proximity definitely helps stoke a genuine rivalry, but so does self-loathing.
Indeed, this is part of the reason a bulk of Arkansas football fans have yet to commit to the very real rivalry with Missouri. After all, if you think you’re better than someone and end up constantly losing to them, delusions have fogged your brain so much that it can’t create anything to fall back on except that feeling of inadequacy, usually manifest as a related person’s fault.