This does NOT mean that everyone will have a recognizable mystical experience over the course of their lives. But it does mean that those who have had them often become more sure of their faith than those who do not have them.
In my case I have had what I believe to be genuine experiences as well as ones that I am not as sure about. I have started to address my reasons for doubting some of them in another blog. But the ones that I believe to be genuine have profoundly changed my outlook on life. When I remember them it is with a feeling of profound inner warmth and I wonder what would have happened in my life if they had not occurred. This is because this type of experience is going to be life-changing and mentally sustaining by definition. In fact, an experience of this type was what lead to my being able to blog the Maxims.