Let us suppose that some giant pharmaceutical company out there has spent long years of research into developing a pill that would make you feel better. With a single dose you would begin to feel yourself growing calmer. Like magic, all the unimportant little worries and insecurities in your life would simply fade away.
You can feel yourself thinking clearer, you sleep better at night and find you're thinking more about important things. The human mind is the most amazing device in the universe; it is a super computer inside your head. It will hold enough information to fill 10,000 hard drives, but it is far from perfect. Primarily because, while a mechanical computer can perform dozens of functions all at once, your conscious computer brain can only do one or two low-grade functions at a time.
Like a guitar amplifier, you can only plug in one or two guitars; after that, no matter how good the musicians play, what comes out becomes a jumble of noise. We have only our eyes and our ears to help us navigate through the world and when they become overloaded such as in an auto accident, we only remember tiny bits and fragments of information and not the event as a whole.
Then there is that other person who's living with you, inside your head. Your subconscious is a whole different mind living in the back room of your brain and it operates independently, working the night shift, once you've gone to sleep. It creates your dreams and it re-fights your battles, back from when you were six or twelve or twenty. Your old girlfriends or boyfriends live in there along with your mom and your dad, your Aunt Martha and the crossing guard from your elementary school.