Comment by CaptainOfCoit

I think there is a wide range of ways to "turn something in the head into words", and sometimes you use the "this is the final point, work towards it" approach and sometimes you use the "not sure what will happen, lets just start talking and go wherever". Different approaches have different tradeoffs, and of course different people have different defaults.

I can confess to not always knowing where I'll end up when I start talking. Similarly, not every time I open my mouth it's just to start but sometimes I do have a goal and conclusion.