Disclaimer: this was written as a response to a question from a very good friend, if this reads too trivial and personal. may be it is. Also, no disrespect meant to any one making any career choice, the opinions expressed reflect my personal bias.
Why are you doing what are you doing? I guess this is one of the most frequently asked question to those of us who are considered not doing a "real job". While I discussed about why I love doing what I am doing years back here, the other question would be, how did I end up doing it. My usual answer is that I ended up doing physics because I was not good at anything else, which strangely does not satisfy people at all.
One tends to think that career choice is a huge decision. May be it is, but as a teenager, it is hard to have that broad global perspective. Our decisions are mostly shaped by what we see happening all around us, in a very local scale. Although in high school essays one writes one wants to be a doctor when one grows up because they hate to see poor people suffering, I have a sneaky feeling that they want to be doctors either because the white coat looks cool in movies, or after reading Robin Cook novels.
I grew up in a very liberal (my parents spent considerable time abroad) yet conservative (in the sense that choosing a non-traditional career was not an option) household in the outskirts of a small town. We were not strikingly affluent, but all the basic luxuries were all there, and fortunately money was never something which influenced my career path. Like all the nerdy kids, I liked mathematics and sciences, but I also found history entertaining and geography enchanting. It is remarkably satisfying when you actually get to set foot on the places you read years back in those books, but I digress. I have to admit that while I liked reading books, of all colors and flavors, I could never find much logic in studying literature, which essentially involved critically dissecting the nice pieces and taking the fun out of them, or memorizing rules of grammar, which is merely a human convention.
My dad is a Ph.D physicist, and so were a few other uncles. My mom studied history. So that possibly helped to shape my initial interest. However, as I approached that inevitable point where I had to decide my "future", there were few other considerations too. Bright (and not so bright) kids left and right were desperately studying engineering in the hope of landing an "easy" software job, and at that impressionable age, that sounded tempting enough. In fact the accepted convention in those days was that the best minds study engineering and medicine, leaving the mediocre kids who could not get through to either study science and humanities subjects. I was fortunate to have been acquainted with computers from an early age, so with my limited (but certainly better than others who wanted to study computer engineering without having the faintest idea of what it is) exposure, I thought that may be a fun subject. But then I was told that you get to use computers in a lot of other disciplines too, and I was happy. Plus studying computers at a good place involved going through some pretty competitive, demanding but dull entrance examinations, and I was not sure if it was worth the hassle. (For the record, yes, I did take those exams, and yes did not get through to where I would have wanted, but at that point I already had my mind made up.)
It is hard to pin down a moment when and how I made up my mind to study physics, but I will try. Many people think, somewhat mistakenly, that I ended up choosing physics because of my family influence. While it is certainly true that there are/were some highly talented and acclaimed physicists I got to talk to, and my dad is an amazing teacher, something so easily accessible and "everyday" does not influence you so much. May be it did subconsciously, I do not know. However, a couple of things happened the summer before I had to decide. I ended up in a summer camp kind of thing (organized by the excellent people at JBNSTS), where toppers from different schools in North Bengal and North-East India gathered and we had short courses on advanced topics. The professor who taught physics, more specifically very beginning quantum mechanics to these bunch of starry-eyed kids was superbly motivational, and we were mesmerized. The class would start in the lecture hall in the afternoon, and at some point, when the lecture hall needed to be locked up, we would just shift to the adjacent cafeteria, and he would continue. Most of us fell in love with physics. Practical considerations meant not all of us taking up physics, but even now when I talk with someone from that group, they fondly talk reminiscence about those lectures. Around the same time, I happened to stumble on this book by James Gleick based on life of Feynman and I just could not put it down. I read though it, all five hundred plus ages in one go, and that was it. As an adolescent you need someone to idolize (Bill Gates for my computer science friends perhaps?), and no matter how cliched it sounds, he was that man. Of course other mundane things helped, that I actually did not get through to those engineering colleges where a lot of people around me expected me to go, but I had good enough grades to get through to perhaps one of the best undergraduate program in physics at that time, and incidentally the aforementioned quantum mechanics
teacher was a faculty there.
As a very young kid, I had a fascination for trains, like all kids do. Once a train driver waived back at me, and that made my day. I thought I wanted a to be train driver. Alas, that never worked out, but as a high energy physicist, I am going places afterall!