Deepak Chopra said this quote

One of the unique things about the human brain is that it can do only what it thinks it can do. The minute you say, My memory isn't what it used to be ... you are actually training your brain to live up to your diminished expectations.Low expectations mean low results.The first rule of super brain is that your brain is always eavesdropping on your thoughts. As it listens, it leans. If you teach it about limitation, your brain will become limited. But what if you do the opposite? What if you teach your brain to be unlimited?