I don't know that most people think about that at all. For me, I have learned not to dismiss the remuninating, reordering, reframing that my brain performs without me deliberately reasoning line by line about it. Limiting my brain to deliberate line by line reasoning would be very limiting and costly.

"Thinking" to me is very much NOT just conscious reasoning. So much of what I think is not done consciously.

Indeed "let me think about it" is often simply giving my brain time to "sit on it", for another expression - only after which will I have enough mind time on the various alternatives for a worthwhile conscious decision.