What you do when there is something on your mind and theres no one to talk to or you know that the other person wouldnt be intrested. Does not mean your crazy, you could just be bored or something, your not crazy unless your answering yourself or the topic is saying "I love you (insert persons name here)".
*This is what happens when a nosy bastard notices you talking to yourself.*
Dumbass: Like OMG! He's talking to himself, ewww! Weirdo!