Richards' exuberantly sung anthem happened "in one grand bash," according to the guitarist. "I had the riff" – that jolting introduction – but no other Stones. "Everybody was late for one reason or another. It was only [saxophonist] Bobby Keys and Jimmy Miller, who was producing. I was like, 'I got this idea, let's just put it down for when the guys arrive.'" Four hours later, "We'd cut it" – with Miller on drums and Richards on bass and slide guitar. Jagger added harmonies later. "I was pretty happy about it," Richards crowed, "which is why it ended up being called 'Happy.'"