Every field looks mysterious and fun from the outside. Your imagination of the work in that field doesn't take into account the fact that you'll have to work with other people, there will be politics, cliques, pointless meetings, fads in the field, disagreeable coworkers, losers, unreliable people. There will also be, at the end of the day, a business that needs to keep afloat, and you'll always have to "just ship it" before it reaches your personal standards. And after you've done everything a few dozen times, on top of everything else, you'll also be bored.

That all said, software development is by far the best career and I'm pretty happy with it.