This aspect will lend you an element of competition that will spark all your interactions. Whether you're on the same team or opposing ones; whether you're playing a game, having an argument, talking about a movie you saw -- you'll push each other to say what you really mean, to focus your energies and efforts and get more done than you would have on your own. There will be your friend's opinionated nature to contend with, of course; they'll have their own ideas and they'll stand right by them, often at the expense of listening to you.
But over time, as you grow to trust and like each other more, you'll allow that helpful influence to start seeping in. You'll challenge each other on your beliefs, which will help you to better define them. If you work together as a team, you'll find that the slightly challenging energy between you will spark creative action.