God is infinitely beyond my comprehension, but I understand Him to be both United and Individual. There is the Father aspect, the Son aspect, and the Spirit, hence the Three-in-One God. Likewise, Jesus the Son established and built the Church, His Bride, as a single united entity. To complicate it, though, the church is also the individual people that make up the Bride. And whenever people are included, things get messy.
Disunity is a problem. In the home, when a husband and wife are not on the same page, the family suffers. At a job, if one manager wants one thing and another something else, there is confusion and a lack of output. In the church, when one member puts their individual wants above another's, there is strife.
What does the solution look like? Simply, we must all aspire to be more selfless. This rings true in all circumstances. If a husband selflessly sacrifices his choice in love for his wife's, the family grows stronger. When the managers meet a compromise, there is efficiency. When the church member adopts the lifestyle of Jesus, the gospel is spread.
Too often we view selflessness as failure. We tend to think that a life of sacrifice is horrible, that we're entitled to certain things just because. In this situation, I think of one of my favorite passages in the bible, Philippians 2:3-11. (Emphasis is mine.)
 Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves.  Let each of you look not only to his own interests, but also to the interests of others.  Have this mind among yourselves, which is yours in Christ Jesus,  who, though he was in the form of God, did not count equality with God a thing to be grasped,  but emptied himself, by taking the form of a servant, being born in the likeness of men.  And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.  Therefore God has highly exalted him and bestowed on him the name that is above every name,  so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth,  and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.If anyone had a right to entitlement and to be selfish, it was Jesus, the Innocent Lamb of God. Instead, out of love He chose to empty Himself of His God-form and become Man, where He then went on to suffer an unimaginably horrible death. Jesus did all of this so that we could have eternal life in heaven and be united with the Trinity in glory. He did not do it to glorify Himself. No, He did it to give glory to the Father.
That's how unity works. It's supernatural. It's awesome. It's something that I'm trying to live out in my life, and it's something I long to see within the church.