It helps keep people from telling me what to do. I grew up in a part of the country where people are very nosy and try to tell you what to do. I think it's because there are a lot of Evangelicals who feel it's their business to tell you what and how to believe.
My beliefs are a bit different than most peoples, not just religion but outlook on life. I don't need anyone trying to tell me how I should live my life. I'm the best person to decide that. Not some stranger who doesn't know me much. Believe me, where I grew up I had people doing it all the time and they were judgmental on my opinions.