Why do some people think it is okay to use your name when you never told it to them?

Like when someone else told it to them or they read it off a name tag? Then yell it out for your attention or walk up and use it? As if you and the person know each other? Who does that and who raised them? Its so fucking rude and just weird. Don't call someone by their first name until they give it to you or been formally introduced. I don't know you or your name, don't call me by my first name asshole. Don't act like we know each other.