Being under 40, although it presents its own challenges, is also quite wonderful compared with other options. For men, it means that whatever your hair has done so far, it’s not as bad as it’s going to get. The women in this group are also likely to look and feel pretty good compared with their projected status in a couple of decades.

There’s also the fact that when you are not yet 40, you can still tell yourself a whole lot of nice things about your future prospects and still believe some of it. If things are going well, you can legitimately think that things are going to get even better. If they’re not, there’s still time to read a host of inspirational, religious, and/or business books and change your game. That’s completely different from being under, say, 50, which is not the new 40, no matter what they say. And forget about being under 60. That’s over before you know it, with all the pertinent implications.

How about these particular under-40s? Not only are they still in the full flush of life as we know it, but they have each done something or other that has gotten them noticed and, quite possibly, rich. Being rich before 40 is even more fun than being rich after it, because you still have an impressive capacity to do something with all that gooey wealth. Being rich after 40 is good too, mind you, but you don’t see people spending a lot of time celebrating you for it. In fact, there’s a fair amount of annoying criticism attached to being loaded and old these days, though it still beats the alternative.

Who, then, are these creative, bold, sassy, gutsy, lucky, relatively youngish people who have achieved so much in so little time? They are, quite simply, the harbingers of tomorrow, moving fast down the highway to replace yesterday’s harbingers, who are still doing quite well, although perhaps doing less harbingering than before. Some have started startups that have started up better than those that, though they started up well, subsequently stopped. Others have nurtured an idea into the full splendor of SWR, or “success without revenue”—a consummation most keenly envied by those of us who must report meaningful EPS each quarter. Others slashed through convention and found new solutions while working at a desk that is also a treadmill, and nobody was allowed to say they looked silly. And then there’s Taylor Swift, whose concerts are attended by little girls in tutus, their older sisters, and their grandmothers. Take that, demographic targeters!

What can we learn from them? They’re aggressive and make their own ways. They don’t care a fig about established protocols. They are rebellious and disruptive right up to the moment there’s a chance that they will be the ones to get disrupted. And when they get rich, they live as stupidly and hedonistically as possible. In short, they are just like you and me, only better looking.

In closing, it would be appropriate, I think, to give a nod to those under 40 who are not mentioned elsewhere—the men and women laboring each day in tiny cubicles, grabbing breakfast, lunch, and dinner from the fancy company cafeteria where all the food is provided for free as long as you eat it fast and get back to your 16-hour workday; who travel in coach from Schenectady to Seattle selling inventory just as their daddies did (only it better be done faster); who don’t have to worry about losing their pensions, because there aren’t any long-term benefits for jobs that age out at 30.

Good luck, unsung under-40s! Sure, life’s just a little bit tougher and weirder and less private than it was in the past. But, hey, at least you’re still pretty young. That counts for plenty, believe me. I’d trade a lot to be able to stay up until 4 a.m. without falling asleep with my face in the bean dip. And you don’t need to be on any annual list to enjoy that, right?

To see the full list of the Fortune 40 Under 40, visit fortune.com/40-under-40.

A version of this article appears in the October 1, 2015 issue of Fortune magazine with the headline “The wisdom of relative youth.”