Adolescents are simply those people who haven't as yet chosen between childhood and adulthood. For as long as anyone tries to hold on to the advantages of childhood—the freedom from responsibility, principally—while seeking to lay claim to the best parts of adulthood, such as independence, he is an adolescent. [...] Eventually most people choose to be adults, or are forced into it. A very few retreat into childhood and never leave it again. A large number remain adolescents for life.
Gene Wolfe, The Book of the Short Sun, Volume 2: In Green's Jungles (2000), Ch. 23.