Honestly, until this point, I always thought everyone did that, personality disorder or not. I just thought that everyone had an active (or relatively active) imagination and just imagined life as they would like it. I frequently daydream. When I was young, it centered around religious dreams that I had; that I was special and important to God. That I was destined for great things. When I got older, it focused around romantic attachments and romantic themes. Now it's a mix of both with bits about being a fabulous wedding cake designer (which I'm going to school for).

But I've always dreamed that I was destined for greatness and a great deal of my disappointment in life came when I realized that I was simply lying to myself.

Like radioactivegirl said, I think it's only dangerous when you can't differentiate between the fantasy and reality. Otherwise, I don't see the harm.