Do you ever stop thinking?

Sometimes after long stretches of silence when I’m with another person, I will ask what they’re thinking or what is on their mind. I think it happens most often during long car trips, but that isn’t particularly relevant.
I would guess the majority of the time the response is “nothing.”

Is that possibly true? I know that my own brain never seems to shut up. I am constantly, actively thinking about something. I often attribute my insomnia to my inability to stop my brain from going on and on. Even when it isn’t interfering with my sleep, I often catch myself thinking about how I wish I could stop thinking. Is everyone like that? Are some people able to not actively think about anything? Are you?