"Back in the Sixties," sighs an ex-hippie lady I know, "everybody was happy. Really. Everybody." Gosh, that wasn't what other people remember. Most teenagers go through a lot of ups and downs, and in the Sixties the Baby Boomers were rollercoastering through their own adolescence. (Some still are.) But as the Boomer Left thinks back to those glory years, they sound like the poet Wordsworth rhapsodizing about the early French Revolution -- before the heads started to roll from Dr. Guillotin's clever new contraption: Bliss was it in that dawn to be alive, But to be young was very...