In yesterday's session we read the Harvard 'wandering mind' study quote, which ended with, "The ability to think about what is not happening is a cognitive achievement that comes at an emotional cost."
Today we have Mark Twain saying basically the same thing in his wonderful, pithy style. This brings up the issue of 'truth'. The 'terrible things' in Twain's life (and in yours!) that did not actually happen were not actually true. They didn't exist in reality, and lived only as thoughts, or figments of his imagination.
Your monkey mind spends a LOT of time in the imaginary/monkey realms. It's critical that you learn to distinguish between what's true and what's merely a concept.
We are going to apply this filter of 'Is it true?' to all of our thoughts. Anxious thoughts can be a great place to try this out, as so many of them are about things that could happen. This state of unrealised potential is imaginary and inherently untrue. As you get good at spotting the obvious ones, you'll start to notice even subtler monkey lies.