This is a trap by Satan to render us inneffective, and it is working- just look at the popularity of this book and others like it.
Paul tells us in Romans 10:7 (the author cites right of the bat) that faith comes from the Word of God. Period. Nothing else. When we base our faith in emotion, that is not a saving faith. That, my friends, is a works-based faith that is not faith at all.
Sorry, folks, just because someone is not raising their hands in worship, not crying crocodile tears during a song, does not mean they are not being 'spiritual'. We are NOT commanded to reach for the next greatest spiritual thing, or 'go farther for Christ'. What does all that mean? Some are called to what the world calls mundane or common. Sorry, Christians are called to obey God, glorify His name, and be salt and light for Him. God will take care of the rest.