When I think about my past religious experiences, I oftentimes find it pleasing to reminisce about those "deep" experiences of my evangelical Christian faith. Numerous worship concerts and revivals come to mind, with the deeply spiritual and emotional atmosphere. Many of the gatherings openly appealed to the emotions.
And I still remember the warm feeling. We all remember the warm feeling.
I think a sort of spiritual misinterpretation happens when the practitioner experiences such circumstances. Modern neurology has seemed to prioritize studies that deal with the interaction of brain chemicals, and some progress has been made on spiritual experiences. It seems plausible that religious experiences involve very complex interactions with different areas of the brain. (Check out NPR for a general overview of some of the discoveries and questions.)
The apparent misinterpretation arises when the subject mentally classifies the said neurological experience as a truly religious spiritual experience. A "spiritual high" results from very emotional, elaborate experiences in religious context. Also, it strengthens cultural religious interactions between the subject and the environmental context of their upbringing. It has the effect of solidifying the religious practitioner's bond with the certain cultural religious memes, as Richard Dawkins would say.