I came across Scientology when I was at University. I read the book Dianetics: The Modern Science of Mental Health, took a basic course and found that it worked.
It was a course in Communication and it got rid of about 50% of my intense shyness. That wasn't the purpose of the course, it was just a side-effect.
The purpose of the course was to improve my ability to communicate with others and it sure accomplished that. So I decided to try other courses and I found that they delivered what they promised too and I continued from there.