Imagine, if you will, that you develop a superpower as a child. The superpower is as follows: when you say a certain set of words, or phrase, the person you are with will leave. S/he won't disappear into a cornfield or anything, s/he would just get up and leave and stay away for a certain minimum amount of time. Say, an hour. After that time, he or she can come back, but doesn't have to. For example, if you say the thing that makes the postman leave, he probably isn't going to come back until the next day (we always had a male postal worker).
Sounds pretty cool. Some bully is bothering you, say the magic words, and BOOM, he has the unrelenting desire to get away from you. A thief tries to mug you? Ha! You've a trick up your sleeve indeed.
Now, here is the wrinkle (because nothing is ever easy): You don't know what the magic words are. They change. So you might be talking to your best friend, and you say a phrase and for what seems like no reason at all, that friend gets up and leaves. And if you know kids, this seems to happen a lot anyways.
So here is the thought experiment: How long is it before you stop talking?