Then, with each decade starting with our 50s, we get happier and happier until we die. This global research, which I've written about in past blog posts, is encouraging for those approaching or surpassing the age of 50.

But, as much as we're boosters of this pro-aging message, I'd like to point out four offsetting facts that are important to note when considering this well-researched theory of the U-curve of Happiness:

1. Just because 47.2 is the low point in the curve of happiness, from an average perspective, this doesn't mean it applies to you. For some, it's 37. For others, it's 57. Your mileage may vary.

2. The more you take your own path early in adulthood, the less likely you'll have a notably lower point. Most Millennials haven't subscribed to their parents' traditional careers or lifestyles. So they're less likely to wake up in midlife and utter the David Byrne lyrics, "And you may find yourself in a beautiful house, with a beautiful wife. And you may ask yourself, 'Well, how did I get here?”

3. Improving life satisfaction doesn't mean you don't deal with difficult circumstances. Our fifties and beyond are full of life challenges — parents passing away, feeling irrelevant or invisible, health and financial concerns, etc. The good news is that as we age, we can develop more emotional resilience to deal with life's challenges. We get good at rolling with the punches!

4. There is some evidence that life satisfaction drops in the last two years of life. Think of this U-curve as a smile that has a little downturn at the end. For many people, the last couple of years of life is full of complex medical interventions. On the other hand, as Stanford's Laura Carstensen has shown, the closer one is to their death, the more one appreciates every moment. It bears repeating, your mileage may vary.