It seems to be a widely held belief that disagreements are a bad thing. Well, I disagree. Especially true in the case of us who are serving the Lord and working to build His Kingdom here on earth, the goal is not constant harmony. The goal ought to be effectiveness.
Look at Paul and Barnabas. The had a sharp disagreement. It was so sharp that they parted ways and scrapped their plans to go back and visit the churches they had started on a previous journey. What a shame . . . or is it?
If you read Acts 15:36-41(see below), you see that their split did not nullify God's work, but actually doubled it! Big win for the Kingdom of God and all the people who were set free by the work of those two teams who eventually went out their separate ways.
I'm not saying you ought to be an argumentative jerk. Take it from a recovering argumentative jerk, that is no place you want to live. But, if your goal is to live in harmony with everyone (like the Bible teaches us in Psalm 133) and you think that means just passively sitting around agreeing with one another, you're missing the point.
God has created you to get out there and make a difference. You're not going to agree with everyone all the time. And sometimes the greatest harmony is achieved when we part ways with one person and align with another.
Of course, you might disagree with me :)