An unofficial A2A request from poor Kartik Khare (poor by credits, that is).
Yes, there is a serious flaw in our system where we are forced to choose a branch before we even enter college. And, once we are in the college, it is next to impossible to change your branch.
In US, people are admitted into a faculty, such as science, or engineering or arts. Their branch, or major as they call it, is not decided until the end of the second year. They have some core courses for that faculty and then they can choose introductory courses of whatever department they like or even take advanced classes as long as they meet the prerequisites. So, the students get sufficient exposure to whatever branch they might be interested in before they have to decide to choose a particular branch. I think that it is a much better system than what we have in India.
Now coming back to the question: "How to choose your branch in the current scenario?" It is indeed a very hard question to answer. Honestly, I had no idea why I wanted to choose electrical engineering. One of my friends whose father was a graduate from IITR and Stanford, was choosing electrical, so I chose electrical in IITD as my first option. I really liked mechanics as well in my 12th grade. I also liked Irodov. But, still I chose electrical and I am quite happy with it. Mechanical in college is very different from mechanics in school, so can't make such a correlation.
Sometimes, one's interest may not be very clear cut. There are always multiple paths. But, one has to choose one path and stick with it. E.g., I really liked geography in school. I also liked history. I liked computer science. But, I chose electrical engineering as my career. Sometimes, you may realize that it is clearly the wrong path that one chose, then one may need to change it, but, unless in exceptional circumstances, it is better to stick with the path that you chose. If you are reasonably satisfied in your stream/job/branch, stick to it. There are ups and downs in every field. If you try too many things, then you get frustrated.
Almost always, you are taking a chance, in choosing a career, in choosing a college, in choosing a company to work for. But, unless there are extenuating circumstances and other clear interests, it is better to stick with what you chose.
"Grass is always greener on the other side." Tom Sawyer's whitewashing the fence is a good example. As soon as you make something a job for somebody, it is no longer interesting. So, such days will be there when you will not find your job and your field interesting. But, soon days will be there when you find it interesting. So, it is better to stick it out, unless the low days are extended and are occurring with a higher frequency. Then, you might need to look at other options.