Thoughts are a little bit like the sound of passing cars.
When a car passes by, you hear it lowly, from a distance at first.
It gets louder as it approaches, and then it fades away.
At some point, you won’t hear the sound of that specific car at all.
That car hasn’t disappeared; it’s still on Earth, driving around.
It’s simply out of your range of hearing.
Sometimes there will be 1 or 2 cars; other times many more, and still others, none.
That’s what thoughts are like.
They are continuously passing through. Even when they’re not right in front of you, one may drive by at any moment. You can’t prevent them.
You can run after them (if you want to), but if you simply sit still, eventually, they’ll fade away.