This blog post by Randy Alcorn is well worth Christians reading, being reminded of, and checking ourselves against. I was made powerfully aware recently in a study of Jesus' parable of the seed along the road (Matthew 13:1–23, Mark 4:1–20, Luke 8:4–15) that we did in our men's group that:
1. The second seed didn't bear fruit because of the trials of our faith coming to bear on us. The Word was received with joy, but then under persecution and trouble they fell away.
2. The third seed grew, it just got choked out by the cares and riches and pleasures of this world, and it was unfruitful (or remained immature).
I believe Randy's article speaks to an antidote to both of these dangers in a powerful and concise way.