Church

1.   To learn.  There's a whole lot of information in the Bible to learn about.  One of the principal reasons to go to church is to learn.  According to Hebrews 4:12, the Bible is full of powerful things to teach us.  Sometimes you learn what the person on stage is teaching, and sometimes you learn something incidental to what they're saying because something they said made you consider something in a new light.  It's unlikely you'll learn everything on your own, so going to church lets you hear insights from different people and learn lessons about things you didn't think to study directly on your own.

2.  To keep yourself on the right path.  Lots of people twist what the Bible says, for various reasons, and if you're not reading your Bible and actively praying and talking to other people about it, you can get off track without realizing it.  It's easy to misunderstand some of the things in the Bible, or to hear something somewhere that sounds right, but might be fundamentally off in some way.  Being in church is one way you can bounce ideas off of people or talk about things you've heard or encountered that might not be quite right.  Talking with other believers is one way to self-correct these little inaccuracies that can build up over time if you're isolated.

3.  To be around other believers.  No, this isn't about conforming to everyone else or trying to be something you're not.  This is about helping you find other people who are struggling with the same things you're struggling with.  Maybe some of them have figured out some things you're still struggling with, and maybe you can help some of them too.  It helps to talk to people who know what you're going through, and can understand where you're coming from.

4.  Worship:  According to Colossians 3:16, Jesus told us worship is important.  Have you ever experienced something that you can't explain, but when you talk to someone else who has experienced it, they understand completely?  Worship is one of those things.  Worship itself can lift your spirits, but worship with a group (corporate worship) is a thing of its own.  When a group of people are worshiping together, there is a power there that simply isn't there when you worship alone.  That power lifts you up and cleanses your soul.  It's like using fire to burn off impurities on the surface of an object.  It's hard to explain, but once you experience it, you'll know exactly what I'm talking about.

5.  Prayer:  Like worship, praying alone is just not the same as praying together with other people. The Bible says that in Matthew 18:19-20 that praying together is powerful.  Synergy is the concept of two or more people or things working together accomplishing more than the sum of each person due to how the interaction happens.  God describes exactly that when we pray together.

6.  Because Jesus told us to:  In Hebrews 10:24-25.  He knows how important it is, so he told us it was.