Chris Willman Senior Music Writer and Chief Music Critic Most of the really essential rituals of American life — religious observances; Halloween and New Year’s Eve; opening day in baseball — are cyclical, endlessly repeatable experiences, independent from individuals or cults of personality. But to that list, a lot of us would add the ritual, stretching past 50 years now, of Bruce Springsteen in concert. And as the world found out last year, that guy can take a sick day.