Perhaps the Zen spirit of Rothbury’s jammy vibe engulfed John Mayer. The singer-guitarist with the biting wit was in chill-out mode for his Sunday evening set. “Waiting on the World to Change,” as smooth and serene as the nearby lake, came across like the most passive-aggressive protest anthem ever written. Guitar licks fell as slow and steady as teardrops on a shuffling “Slow Dancing in a Burning Room.” Even a cover of the blues standard “Crossroads” sounded unnervingly polite. Still, the set wasn’t without its highlights, including the soul-flecked ballad “Gravity,” a song far more weightless than its titles might suggest.