Thoughts are programmed. They are meant to make you live out a fate that was instilled at your apparent birth.
As thoughts are presented to your awareness, you have the choice to dismiss them and live spontaneously.
Said dismissal can be done by shifting the focus of attention to something else. If this proves difficult, the choice can be made to go with the thought and fully feel the sensation of it.
In my experience, the latter makes it more obvious that the majority of thoughts aren't worthy of attention.
At this point, I simply say "go away" to idle thoughts and they scram immediately.
Whatever reactions arise and whatever is done through the body is no one's choice...
So it's very important to keep watch over thoughts and not let anything unworthy defile your mind.
With fragrant blessings and much Aloha!