Have you ever had conversations in your head?

You thought of someone, and your brain churned up entire conversations that could happen between you two... What he/she would say and what you would say and how the conversation would flow... and how things would end

Do you find yourself thinking from the other person's perspective more often? Like what would they think of you? What would they say to you?
Does it ever hold you back from approaching them, or talking to them?