And for lack of a better phrase, some people are more mystically inclined. Dan Barker, an evangelical preacher turned atheist, says he can still pray himself into a spiritual state where he feels the "Holy Spirit" operating inside. That's just where he falls on the bell shaped curve of mystical inclination. Others couldn't feel the "Holy Spirit" if their life depended on it.
Barker attributes the "Holy Spirit" sensation as some kind of psychological experience instead of an outside force. But most people who fall on the curve at the same place as Barker are probably religious.