There's been a lot of talk lately in our house about career choices. This has, in turn, led to my thinking through the objective goals in a career choice. The following is my best shot at listing and prioritizing the things to consider when picking a career area. Much of it is personal and subjective, of course.
First and foremost, you should have a passion for it. If you don't, it will be a long boring life. If you do, you'll be willing to spend the hours required to be really good at it. Of course, it's not always easy to find the thing you're really, long-term passionate about. Which argues for checking out a number of areas early on. I think most people know it when they see it. Myself, I found programming during high school, and have since spent probably an average of seventy hours a week (3,640 hours a year) doing it and loving doing it. Having started 35 years ago, that makes for 127,400 hours, give or take.
Second, it should be a positive sum game. Game theorists divide games into zero sum games, where the number of points is fixed, so if someone wins, someone else must lose; positive sum games, where more than one person can win; and negative sum games, where everyone loses points. Some career areas, like marketing and politics, are zero sum games. (Politics, when it focuses on finding solution regardless of sides, can be positive sum, but it's very seldom played that way.) If you love competing and winning, that can be a great choice, but it's not for me. Careers that involve creating something new (knowledge, products, etc.) are generally positive sum. Of course, there's often competition between groups or companies, so it's not always the case that everyone wins. But even when my group loses, I still get to use the product of the winning group (whether it's new science or a commercial software application).
Third, it should be an area that's active and expanding. It's much more fun to work with computers, whose power (and thus the set of potential applications) doubles every couple years, than it is to work on refrigerator design, which hasn't changed much for decades. Areas where new discoveries happen regularly provide more opportunities and more material to build your own work on top of. Today, that probably means computers, biotechnology, or nanotechnology; but there are dozens of other possibilities as well.
Fourth, for me at least, something on the border between science and engineering is ideal, where you can surf back and forth between the two. Science is great because you discover things that no one has ever known before, and because the potential impact on civilization is huge. But there's about a ten year minimum delay between a major discovery and its use in everyday products. Engineering is great because people actually use what you create directly, and it happens while you watch. Sitting between the two gives you the best of both, and lets you help reduce that delay from discovery to use.
Did I think all this through when I made my own career choice? No way. I took a course in programming, thought it was the coolest, most fun thing I'd ever seen, and never looked back. The thinking above is all after-the-fact, justify-the-decision-after-it's-made stuff.
My wife and I took our daughter (four years old at the time) to the hospital. At the time, she had a white stuffed teddy bear with a red tutu that we all called "ballerina teddy bear," who she brought along. We checked in and she got a bracelet with her name, and ballerina teddy bear got one too. Then we met with the anesthesiologist, who was very friendly and helpful. After a few minutes, he took her off to the operating room, while we had to stay behind.