(Outside the Louvre, fully backpacked up, August 2008. I took full advantage of their coat/bag check)
For me, travel is attractive for a couple of primary reasons: (1) it's intellectual and (2) it's challenging. I think the intellectual part is easy to understand. Traveling allows you to see places that have affected world history, gain a context and understanding of people and groups of people, and just generally get a more complete picture of how the world runs. But then again, there are many intellectual pursuits, such as... reading The Economist, or playing chess. But I don't really do either of those things, and heck, I'm in grad school, I certainly get enough of the intellectual part. On the other hand, the really attractive part of travel is the way in which it is a personal challenge.
Taking the point to hyperbole, the thrill in traveling, is, to me, the thrill of survival. To break it down to such a basic level is a huge exaggeration in some aspects, less so in others. A lot of travel is simple and easy and your entire day will go as planned. On the other hand, a lot of it is completely uncontrollable--the store only takes cash, the menu has no English, or sorry, if the buses don't fill up, they cancel that route for the day. As I mentioned before, you have to always be on your toes when you travel and make sure you have the basics covered: somewhere to sleep, something to eat, some way to get home. That is the survival part, and that's the part that is both frightening and the biggest draw for me. It's like snowboarding--I'll pick a run that scares the crap out of me when I think about it, but making it down that is such an accomplished feeling.
I'd also like to take this opportunity to say that in some regards, I do feel as though a big part of what feels so challenging and rewarding is the fact that I've done much of it alone. There are definitely many times in which I've wished I was traveling with someone else, just to have someone to share the experience with or to simply feel a bit safer around, but then again, in some ways that's the point. I do feel a little bit less safe on my own, and it's a more gratifying experience to make it back home again. (Not that I would ever put myself in a position where I was truly worried about making it back home again.)
So there it is, I'm a thrill-seeker and I'm addicted to travel. I do it not only to learn something but also because it scares me. Traveling alone is a huge part of that; it has made me a more resourceful and adaptable person and more confident in general. Of course it has downsides, but if you ever want to feel like you can do anything in the world (and have that almost literally be true), book yourself a plane ticket to somewhere, alone, and have a blast.

