Believe what you want, but it's not just a theory; it's been reasearched and supported. Psychologists measured brain activity during sleep, and there is an increase in activity during REM sleep when you are dreaming. There have also been studies where they have shown that a lack of dreaming (whether or not the person sleeps) causes a person to be unable to function properly. Hence my statement that dreaming is a need. If someone wasn't dreaming at all, they would not be able to function after a few days. That is why I said that you probably just didn't remember your dreams during that period. Crawl is right about drugs that aid sleep causing a lack of dreams though.