It’s interesting to reflect on the implications of American slang for approbation and enthusiasm. Old-timey slang included terms like “the bee’s knees,” “cat’s pajamas” and “copacetic.” They were humorous and light-hearted expressions of appreciation, without the expectation of control in the relationship with the admired object. The 1950s beat slang saw a bemused irreverence for daddio, slouching into passivity when the with-it were cats and chicks, and things were cool, man. The ’60s saw more...