If children did come with a manual, parenting would be much easier! There is a wonderful Huffington Post article describing the importance of parent education.
The article begins "You'd never hire someone to do the most difficult and important job on Earth, give them the responsibility to care for your most valuable asset, and toss him or her head first into the job without any training. Yet, we do it every day as new parents, each time a child is born."
The author goes on to describe specific examples of the impact of parenting and parent education. How we choose to parent certainly affects our family's future happiness.