People who go to the hospital go only for one reason: they have concerns about their health.  Either they know definitely that they are sick, or they have reasons to believe that they might be sick.  Those with no health concerns usually stay out of hospitals and healthcare-related facilities.  

In the same way, people go to church because they either know for sure they are sinners, or suspect they are sinners, and need to get right with God.  People who are one hundred percent sure they are not sinners are free to stay out of church.  The church helps sinners to know and understand what the Bible says about them, and what they need to do to receive forgiveness.  

After salvation, a person is still a sinner, except that he or she has been saved by grace.  The sinful nature still exists and that is why he or she still needs church.  The Church is the body of Christ, comprising of saved sinners.  The ministry of the church is to serve God by serving each other, and mankind as a whole for the glory of God.  Through the Bible, the church teaches the saved sinner how not to be controlled by the old nature, but instead walk in obedience to what the Word of God says.  The Christian walk is a day to day way of life.  Until we see the Savior face to face, either at death or at the rapture, we will need the teaching, the influence, and the support of the church!  

If you know (not if you think) you are not a sinner, then feel free to stay out of church, but if you are not sure, please come to church.  I know the reason for your assumption that you are not a sinner is based on how highly you think about yourself, and the fact that you probably know other people you consider worse than yourself.  But let me assure you: you are a sinner!  How do I know that?  The Bible says so. “All (you included) have sinned and fall short of the glory of God” (Rom 3:23).  Sorry to disappoint you, but you do need church.  

I think I know your next argument; it goes something like this: “I don’t want to go to church; the Church is full of hypocrites.” That is the whole point; you are right!  Church people, however, are not trying to be hypocrites; they appear that way because they are imperfect people, still sinners like I said before.  That is why they go to church (the spiritual hospital, if you like); to learn more about how to get better and not appear hypocritical, and also to get help, support, and encouragement from other imperfect people who have also been saved by grace.  Jesus Himself said, ‘I have not come to call the righteous, but sinners” (Mt 9:13b).  So the Church is full of sinners, just as the hospital is full of sick people. They are all looking for HELP; be it medical or spiritual, it is still HELP! Jesus said, “It is not the healthy who need a doctor, but the sick” (Mt 9:12).

If you are in church, it means you know you are a sinner, and so are the other people you see in the pews.  Please don’t judge or condemn any of them.  Focus on yourself.  God has not called you to judge; He has called you to “Learn from Me” (Mt 11:29a).  There is so much to learn from Him and practice that, if we obey this command, we will have no time to be judging or critiquing others.  We all need to be part of the Church, the body of Christ, the bride of Christ!