What is the cause of imaginary dialogues in mind?

Most of the time, I have conversations in mind. Most of them, there is person , interviewing me. Other person: *"Why don't you like that ?"* Me: *"I don't like it because ..."* This doesn't happen in real world because it is an egoish thing. What is the cause of this ?. Is this the pride ? How do I stop this without forcing it ? (I'm aware of these kind of thoughts and I turn the direction when I caught them.) I am looking for an answer according to the Buddhism.