Is there such thing as a good sleep pattern or a good sleep rhythm?

Yes. A good sleep pattern is regular. It consists of a single sleep period of about 6 - 8 hrs, with or without a siesta, at the end of that period you feel refreshed and not sleepy anymore.
Yes. There are several phases of sleep and one of the most important levels for maximum rest and renovation is delta phase. This is the deepest level of sleep in which hgh (human growth hormone) is released and in adults provides one of the most potented hormones that naturally helps prevent tissue and organ breakdown.