You do not control your thoughts until you stop thinking and start observing them. This is something very few people are capable of because they’ve spent their entire life allowing their thoughts to control them. For example.

Imagine a friend, an enemy and a bar of chocolate, not at the same time or you could end up with a movie script, the thoughts you generated by the image of each were not controlled by you, they just popped into your mind automatically based on your previous experiences with them. If you had an emotional reaction to those thoughts, you’re not in control of your thinking because you are allowing them to control you. If you didn’t have an emotional response, you could teach other people how to observe and not think.
Observing your thoughts to gain control over your thinking is not a new phenomenon. It’s been around for as long as people have had the ability to meditate, I just find it interesting to think about.
I’ll leave you with one final thought. When you observe yourself thinking about something else, you can tell yourself to let it go. You may even listen eventually.

P.S. people who illicit an emotional response have control over you. Remember, you gave them that control.