I agree that childhood is the best part of everybody's life. I do not know someone that cannot remember his joyful childhood and sweet adventures of school time. In my opinion childhood is unforgettable and lovely, because of lack of responsibility, enjoying life and eventually hope to feature.
As an adult you have several responsibilities, In your society, at work and in family. For example if you do something wrong at work, your boss scold you, or if you run fast in highway police arrest you, but when you are child you do not have any responsibility. You live free without thinking to your behaviors.
I think the best part of life is our childhood, because I had a lot of joyful time in that duration.