...when they ask what you offer to replace their faith, or they imply that theirs is the only hope for the massive problems in the world and ask "where (else) are we to go?".
"[T]hat I have no remedy for all the sorrows of the world is no reason for my accepting yours. It simply supports the strong probability that yours is a fake."
I came across this quote in a political discussion, but I thought it fits well with the classic Witness claim of being the only hope for a person in today's world.