Each dream is a mixture of our biological instincts, our cultural assumptions and our own personal experience. As we dream, our brains create stories from these ingredients, sometimes to "replay" recent events, and at times voice concerns that our waking minds are not yet ready to face. These stories are occasionally laced with complicated plots, and sometimes populated with elaborate visual or verbal puns that help us unlock their meaning.

......more at .....

http://health.discovery.com/centers/sleepdreams/universaldreams/universaldreams.html