When You are in 12th Standard or You drop a year for JEE . You don't Know about all the branches and the main important thing is that You don't about different specialization Under Different Branches . So during the time of counselling , You have to select one branch and you are not knowing whatever you are choosing for Your Career . Once think You selected any branch but after studing one semester or two. If You dont like that course what will happen ? You are not going to do any thing big . because if you dont love your work then how can you do something better something innovative. So before Choosing Your career You should understand about every branches properly . So that You dont regret in Future.