In my own opinion privacy can be said to be the state of being free from the constant disturbance, the act of being free to be ones self without being looked at or judges. Everyone needs his or her privacy.
But most people tend to be really annoying why because they don't understand that word "privacy". You might want to just rest at home for a day and a friend barges into your house and pulls you out for a party.
Even at your home one or two person's would never leave you be.They always want to know what you do, whom you call, whom you hang out with, who your friends are, what their parents do. This is all good but a little bit of privacy would be good.