I like what Perry Noble says on his blog. Here are some reasons he gave about the church being important...
#1 - If church isn’t that important - then why does Matthew 16:18 say that Jesus built it? Would the Son of God actually spend time building something that was worthless?
#2 - If church isn’t that important - then why does Scripture say in Acts 20:28 say that Jesus shed His blood for it? Would the Son of God have been willing to endure the suffering He went through for a meaningless organization?
#3 - If church isn’t that important - then why does Ephesians 1:22 & Colossians 1:18 say that Jesus is the Head of it? Would Jesus REALLY be the Head of something insignificant and trivial?
#4 - If church isn’t that important, if church isn’t “needed” to learn about God…then why does Ephesians 3:10 say that it was through the church that the wisdom of God should be made known?
You also can't leave this out. "Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another—and all the more as you see the Day approaching." (Hebrews 10:25)
In my years of ministry, I have met people that both do attend and don't attend church, that do not have a clue what it is about. What is it about? What is it's role? What is our job as Christians in it?
Please let me encourage you. If you are a believer and you don't attend a church for whatever reason, please study about the church. Understand what it is really about. Maybe you haven't been to a church that is doing it's job. That could be your first problem Maybe you haven't stayed long enough, or have not gotten involved. That might be the main problem.
If you are attending a church, but are not giving back to it in any way (serving). Shame on you. Get involved. Jesus died for the church. Come on now!

Well said! Thank you for voicing that, Doug.