Reihan goes on an enjoyable tangent:

Consider the rise in the amount of leisure U.S. adults have experienced over the last several decades. One reason we feel harried and stressed despite an increase in total leisure time is that there are more competing uses for leisure time in an affluent society.

Our brains hunger for novelty, and our service-driven economy devotes a great deal of brainpower to the manufacture of novelty. This novelty helps shape and structure our identities as we choose our various portfolios of “eclectic” preferences, interests, and affiliations. And so new identity groups and subgroups are arising all the time, and merging, splitting, budding, absorbing each other, etc.