Meh to the commenter who called it "maladaptive".
As a general rule of thumb: if some behaviour or trait makes you successful or is common, it is considered normal or good. Think of authors for example, they constantly have conversations of imaginary people in their head; they have conversations with them, they live in their mind etc... Are they considered crazy?
People in ancient times supposedly didn't have the ability to read in silence - everyone read aloud back then, even when they were alone by themselves. If you did this today, people would call you mentally ill.
Or, to paraphrase Thomas Szasz: If you talk to God, you are religious - if God talks to you, you are mentally ill.
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You would do good to stop looking for pathologies within yourself and start considering whatever you do as a) probably quite common and b) natural, free from moral judgement, neither healthy nor pathological
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So: if you rehearsing conversations with people you know in real life in your head was a sign of 'mental illness', what would we have to say about grown up people who talk aloud to an imaginary being who lives in the sky, created the earth and who they believe listens to their wishes, and believing he will fulfill them via supernatural intervention?
You guessed it. But it's a collective delusion, thus not considered "maladaptive"; at least you don't believe that your friends will remember the imaginary conversations you had with them when you meet them again in real life.