We need to stop giving people excuses not to believe in God. You've probably heard the expression "I believe in God, just not organized religion." I don't think people would say that if the church truly lived like we are called to live. The expression would change to "I can't deny what the church does, but I don't believe in their God." At least then they'd address their rejection of God rather than use the church as a scapegoat.
The core problem isn't the fact that we're lukewarm, halfhearted, or stagnant Christians. The crux of it all is why we are this way, and it is because we have an inaccurate view of God. We see Him as a benevolent Being who is satisfied when people manage to fit Him into their lives in some small way. We forget that God never had an identity crisis. He knows that He's great and deserves to be the center of our lives. Jesus came humbly as a servant, but He never begs us to give Him some small part of ourselves. He commands everything from His followers.
There is an epidemic of spiritual amnesia going around, and none of us is immune. No matter how many fascinating details we learn about God's creation, no matter how many pictures we see of His galaxies, and no matter how many sunsets we watch, we still forget. Most of us know that we are supposed to love and fear God; that we are supposed to read our Bibles and pray so that we can get to know Him better; that we are supposed to worship Him with our lives. But actually living it out is challenging.
Because we don't often think about the reality of who God is, we quickly forget that He is worthy to be worshipped and loved.