Oh, my. The happiness studies are coming fast and furious.
On Slate, one of Monday's stories was "Why Old People Are Happier Than You." (Interesting art choice, with the photo of the woman who looks less happy than about to tell you that she's fixing to get a migraine.)
The article cites a study by two economists who looked into happiness and found a U-curve--that this, people start out happy, get progressively less happier until about age 45, then get progressively happier.
(They also found that the richer tend to be happier than the poor, according to the article, although money tends to have a complex relationship with happiness. According to other sources I've read, though, the difference in happiness between the rich and the poor tends to be pretty slim, unless you're talking sub-Saharan African kind of poverty.)
So, basically, there is such a thing as a mid-life crisis, if by "crisis," you mean "the unhappiest age you'll ever be in your life."
In The Atlantic, there's a little write-up on a psychological study that finds that "regret over indulgence and gluttony diminishes with time, but regret over missing out--doing the responsible thing and deferring gratification--only increases." In other words, it's like that old saw: the elderly report they only regret what they failed to do, not what they did.
Eh. First off, this study was published in the Journal of Consumer Research, which leads me to believe in the existence of people who'd benefit from us believing this. God knows I'm no heavyweight in the self-control department, but I have to be skeptical of any research that exhorts us to spend more.
Also, I wonder what kind of lives this study looked into. Because on my death bed, I'm pretty sure I won't be looking at my beloveds and croaking out, "Dahlings. If only. I'd purchased more. Consumer goods."
I think Mihaly Csikzsentmihalyi (that's pronounced CHICK-sent-me-high-ee), author of Flow--a book about living the good life not through pleasure alone--might back me up on this.