It is said that the doctrine of Predestination is not a necessary tool for preaching. I believe it is true to some extend.
When Neil Armstrong walked on the moon, how many remember the names of those researchers, scientists and directors behind the NASA project? Who's going to talk about man on the moon if you don't tell them Neil Armstrong first?
It is said that God will not help those who don't help themselves. Many couldn't accept Predestination because they view this statement from an observer's reference frame. Unless you've truly taken the effort to help yourself and further study the sovereignty of God and the true disgusting nature of our fallen state, it is rather difficult to imagine that one could get this far if God had not laid the hidden steps, a set of very personal steps first.