To become an adult means to grow accustomed, and therefore to grow blind.

 To become an adult means to grow accustomed, and therefore to grow blind. The things children and the young spend their days pondering, adults do not even perceive, for their perception has long since adapted to the world. The adult mind is an automaton; following a predictable pattern conditioned to read only what it already knows, derived from its accumulation of experience. Even its most radical works and acts are actually mechanical. It is a rust that those newly arrived in the world do not possess.