We feel rich in stuff but completely broke when it comes to time. Research by Mogilner and colleagues found that feeling "time-rich" predicts happiness more than money or possessions. Billy learned this when the boat he bought for freedom became a little captain barking orders at him, his "optimal fun strategy" wasn't actually fun for anyone. The fix? Calculate the cost of every "yes" by visualizing what you're saying "no" to. Look at your calendar this week, find one thing to decline, and protect that freed-up hour like a gold bar.