We are a people who need fellowship with others. God has designed humans to be this way. It's not easy for all personality types to engage in fellowship with others, but that doesn't mean we don't all need it.
Consider the creation account in Genesis. God created Adam and was in fellowship with him. Before the Fall all of creation was as it should have been and yet God deemed it "not good" for man to be alone (Genesis 2:18). You would think that man in fellowship with God only before the Fall would be perfect, but God didn't see it that way. God created man to be in fellowship with others. I realize that Eve was created to partner with Adam in ways that only husbands and wives are to partner (and "Hallelujah!" for those ways!), but I still believe there is a more general need for human interaction in all of us that is a part of how we've been wired.
The Trinity exists in perfect fellowship, independent of man, with three persons in one being and, man has been made in God's image (Genesis 1:26). I believe the image of God in man reflects and longs for the things that God experiences perfectly whether the person is saved or not. So, the need for fellowship is not reserved for the Church. It is a basic human requirement.
The rewards of community and the effects of isolation are manifested in good and bad ways throughout all levels of society and stages of life: parents put kids in time out, teens often seek belonging and community through gangs, prisoners are isolated to solitary confinement, people join clubs to discuss books and movies and wine, etc.
The Church, however, has to approach this need for community from a biblical perspective. If believers are to be devoted to the purposes of God since He has set us aside as His holy people (1 Peter 2:9), we need to understand community through His eyes.
As Christians, we do not have the right to avoid people in order to appease our preferences. We have been called to God's purposes. We are different parts of the body of Christ fit together by Him and submitted to His headship for His glory (Ephesians 4:11-16)
May we, as believers, better reflect God's nature in the ways we love our neighbors. May we engage our brothers and sisters in Christ in fellowship and unity to the glory of God. May we point people to Christ as we interact with each other and submit to the freedom He brings in overcoming our differences.
I'm so thankful for the community God has blessed me with and am hopeful that you will seek out and find it in your life, as well. It's not always easy or comfortable to be part of the Church, but it is our purpose and calling!