One interesting factor we've found in planting a new church is that "gathering the lost" is not as easy as it sounds.
Many lost people don't know it. Some lost people are in denial. Others who are lost are quite lost and take a lot of work and effort to become "found" again.
Then there are people who are believers, but for various reasons, live like lost people. That is, I think, perhaps the most serious kind of "lost" there is.