You learn what drives and motivates your children. When you watch children over time, you begin to get an idea of what interests them, how they explore and what they're trying to learn. Observation enables you to provide children with avenues to further their explorations. When you know your child is working on pouring, you can supply her with a set of plastic cups in the bathtub. Observation gives you a chance to see your children as they are.
Most parents have some expectations about who they want their children to be.
Observation can help you answer that question. Observation enables you to respond to each child as a unique individual. Otherwise I'm coming in ready to interact with all the children his age I've ever been with before, rather than this particular child. This can help you move beyond your own frustration and respond more empathetically to unsuccessful behavior. Observation lets your child know she is important to you.