Did this ever happen to you? Some time ago, I was walking down the block and then someone said 'hi, how are you.' I'm wondering who he is, and then I realized he's not talking to me. He's wearing an earpiece and talking on the phone.
I can imagine someone from the past coming to nowadays and then going back to the past, and some one asks the time traveller 'what's the future like?' And he replies, 'Everyone talks to themselves.'