Love must be sincere. Hate what is evil; cling to what is good. Be devoted to one another in brotherly love. Honor one another above yourselves. Never be lacking in zeal, but keep your spiritual fervor, serving the Lord. Be joyful in hope, patient in affliction, faithful in prayer. Share with God's people who are in need. Practice hospitality. Romans 12:9-13
Have you ever been on a team that didn't act like a team? Back in the day I was known around my neighborhood by one of the parents as Mr. Ball Hog (granted, he didn't get points for originality but 35 years later I remember it). If I got the ball in football or baseball I wasn't about to pass it or share it with anyone (running across the field to tag someone out. I wanted the score. I wanted to do it myself. I wanted the glory of “doing it my way.” Every time. Obviously I didn't endear my friends because they wanted to play too. They were on my team but I didn't appreciate it.
I find the same kind of reality in the Christian world too, though, usually more subtle than my ball hogging antics! We have a team, a winning team. On our team are a lot of very different personalities and giftings. Friction is bound to occur between teammates because, well, none of us have quite “arrived” yet. And yet, our Manager has told us we need to play well together. If we don't our game will suffer. We'll still win in the end, but boy will it be an “ugly win.”
Instead of complaining against your fellow Believer, pray for him or her. You may even discover that the real “issue” wasn't with him/her after all.