Toddlers live in a constant state of wonder. Everything is new. Each object is full of new color, shape, weight, and orifice-filling potential. The tragedy of this blissful life is that it will die a slow death with the aging of experience.
Things become known.
Secrets are uncovered.
By the time we leave adolescence for adulthood we are threatened with life-killing boredom, having lost all sensation of wonder because we can't find anything that is really new.