Why do my parents see a need for me to interact socially and have fun?? How can I convince them it is a waste?

I hope you realize that you are not able to be completely alone even as an adult. You live in the real world and you HAVE to learn how to deal with people. If nothing else, just to hold a steady job you need to have people skills. Find people who share the same interests. Nothing saying you have to go to sports or parties if that isn't your thing. But the reality is we are social beings and you can not survive without human interaction.