It's getting more and more that doing something in particular passably - let alone well - requires thousands if not tens of thousands of hours of practice, and complete immersion and thirst for information within that knowledge domain.
Healthy or not, it's how the world works. If you spend that much time learning to be a good hacker and developing both the passion and understanding to create interesting software products, just about anything else you do "once in a while" is something in which you're going to be no more than a mere dabbler. Of course, there are exceptions; I know several Renaissance Men that seem to be impeccably good at numerous things that constitute universes of very non-trivial complexity in themselves, and have always been omni-curious, well-read, and just generally knowledgeable about, well, just about anything. But they are the exception, and even in their case, areas of sweeping general knowledge don't have the same economic or practical utility as narrow corridors of highly specific knowledge.
It's just a trade-off of the epoch in which we live. There are only so many hours in the day, and that's just how it goes.
Personally, I have always been a person with broad interests in a variety of unrelated areas that I frequently nurse. But, I have no illusions about excelling and being truly proficient at more than one of those domains - maybe two someday, if I'm lucky - in a way that's useful and can make a meaningful impact on the world. I'd be the last to protest diversification for the sake of health and sanity, but it's important to realise that it's just that.
If you spent the last ten years intensely immersed in programming for most fruitful hours of your waking life, but also "occasionally" like to screw around with automobile mechanics, then it's a basically immutable fact that you're going to be an eminently better programmer than an auto mechanic. And while it may be fun and valuable to exercise your mind in both areas, the auto mechanic side of you isn't going to get the same kind of satisfaction that comes from the efficacy and power of competence and deep, erudite knowledge. It's being able to accomplish something concrete, nontrivial and lasting that gives programmers that high, which is why so few (outside academia) write toy code just for the fun of it that nobody's ever going to use.
The point is, I think that most intelligent people want to apply their skills and capabilities in ways that have a measurable displacement in the real world. That takes so much time, effort and devotion that it leaves tragically little time for other things. And I think that's why well-meaning people end up in the "tunnel vision" of their "narrow" professional self-concept; it's a cross we bear for being really good at what we do, or striving to be.
With regard to Relay for Life, I'm going to end with a quote from Dmitry Orlov's essay, "Thriving in the Age of Collapse," which is otherwise on the wholly different topic of his very pessimistic views of energy consumption sustainability. (http://nosedive.org/backup/orlov.htm)
I think it sums up my view of the usefulness of participating in such things, though:
"Am I being overly optimistic about the promise of a reformed American suburbia? Some people are ready to declare suburbia to be at an end. But then I know that Americans are very much driven to hyperbole, always willing to put an end to something certifiably unstoppable (war, AIDS, cancer, poverty, global warming), usually by making a small charitable donation, by wearing a colorful plastic bracelet, or by going for a walk, a run, or a bicycle ride. Below the charming, childlike confidence and optimism of such ventures lurks a culturally ingrained inability to grasp something basic: not all problems are solvable.
And thus I discern an element of wishful thinking in the idea that suburbia is going to conveniently disappear, and that everyone who lives there will simply go and live someplace else. A cabin in the woods, perhaps? Or a picturesque desert island? How about a space colony? Nor do I find it plausible that half the U.S. population will lay down and die shortly after they discover that some of their cars no longer run or that their kitchen appliances no longer work. And so I find it safe to think that most of the existing infestations of Suburbia americans are ineradicable, but that the evolutionary pressure of a chronic energy shortage will force them to evolve into something much less energy-intensive. Whether, in each case, that something will turn out to be absolutely horrible, or quite pleasant, will depend on many things."