Leave me alone please!

I get very much frustrated when people ask me "How long will u keep studying?"...being a PhD student I find it very difficult to answer. Since I have decided to stay in academics, study is a never ending process for me. I get paid for that only. I don't know how to convince those people that people can earn "good" money without finishing their studies also. I don't know much about the cities, but in rural areas people still prefer their children to become doctor, engineer or bureaucrats. In fact when I decided not to do engineering or medical, my father sent me to study in Delhi thinking that after my B.Sc. I will appear Civil Service examination. But nobody asked me why I want to do B.Sc. in Physics: to become a bureaucrat or because of my interest in Physics. Anyway after cracking IIT post graduate entrance exam, I somehow convinced my parents that IIT is a big place and I will do good if I go there. After spending almost four years in IIT, still my parents think I will appear Civil service exam after I pass out from here. I do not know how to keep my family as well as the people in my locality happy. I have realized now that its better not to visit home before finishing my PhD, so as not to let these depressing feelings come in between me and my research. I am really happy with the fact that I am doing whatever I like, but may be people would have liked me to do what they like. They do it everywhere, not just in case of career, but in case of marriage also. They never let you marry the person you love to be with throughout your life, its them who will decide whom you gonna marry. I can't believe I am living in 21st Century and in a country which has one of the fastest growing economy and a future superpower( by 2020 as Kalam said). I would just say those who can't appreciate what I am doing then please leave me alone!