It seems bizarre to think that you're entitled to a stranger's time — and that's exactly what's happening when you try to take a selfie with a celebrity. Whatever relationship you have with them is completely one-sided, they might be your “favorite,” but they — meanwhile — have no idea that you even exist. So when you rock up to them at their daughter's birthday party, demanding their attention, it's pretty safe to say that's going to go about as well — and be as well received — as it would wit…