" At this point, let’s take a moment to recall that defusion is all about acceptance. The idea is not to get rid of these images but to let go of struggling with them. Why should you accept them? Because the reality is, for the rest of your life, in one form or another, scary pictures will appear. Remember, your mind evolved from a “don’t get killed” device. It saved your ancestors’ hides by sending them warnings: an image of a bear sleeping in the back of that cave or of a hungry sabre-toothed tiger crouched on that rock. So after a hundred thousand years of evolution, your mind is not suddenly going to say, “Oh, hang on a minute. I no longer live in a cave, vulnerable to bears and tigers—I don’t need to keep sending out these warnings anymore.” Sorry, but minds don’t work like that. "

― Russ Harris , The Happiness Trap: How to Stop Struggling and Start Living: A Guide to ACT