The mental models that we create for ourselves are powerful. Our models create the context in which we operate or the lens in which we view the world.
The market, like Nature, is a treacherous place. The unfortunate fellow on the left is a tomato hornworm-picture courtesy of me and my tomato plant. If you are a gardener you know him for his voracious appetite. Once attached to your tomato plant, he can defoliate it in short time.
Nature loves balance. This gluttoneous fellow serves as a host for the parasitic wasp's braconid and ichneumonid. The wasp lays its eggs, and the pupae feast on on the flesh of of the horn worm. The open casing is where the wasp emerges. (Editor's note: ewwwwwwww!!)
As individual investors and traders, we often feel like the David against the Goliath. The next time you feel prone to lamenting the gluttonous caterpillars that are feasting on your portfolio, I would encourage you to think of the braconid wasp. It is nimble and opportunistic. It worked for David; it works for the braconid; it will work for you. But it will not work if you are mired down in another mental model that prevents your empowering your actions.