Anyone else have a default topic that your brain turns to when idle?

My train of thought has gone down the same path hundreds of times when bored. There is no new realisation about that topic that remains to be had. And yet every time my inner monologue goes down the same well trodden path. It almost hurts at this point. I don't really choose the topic, it's usually just one I've come into contact with repeatedly and they change over the years. I commute by bus and the monologue is always at the same point at the same point in the journey. I am going crazy. How do I turn this off.