Yep... I retired at 53. A couple of reasons. 1) I was completely fed up with giving thousands and thousands of dollars to the government so they could buy obama phones or whatever with it. 2) We have enough to live comfortable for the rest of our life. 3) I do the things I WANT to do now. Golf, real estate, teach guitar lessons, teach naturalization classes, volunteer at church, volunteer at the hospital, more Golf, ride with the top down, swim, go to the gym, more Golf, and enjoy life.
As you say busier and happier. I'm not sure about busier cause work was CRAZY the last few years... but way HAPPIER!