Americans are having something of an anger management moment. Tweeters hated on NBC’s coverage of the Olympics, campaign crowds heckle both presidential candidates, and viewers lost interest in the last season of “American Idol” because the judges were too nice.Last week, the presidential campaign took its turn, detouring from health care and tax cuts to focus on which candidate was the angry one. First, Mitt Romney accused Barack Obama and Joe Biden of running an “angry and desperate” campaign.