The beliefs that become mindsets transcend preferences, learned facts, or intellectual opinions. They are core beliefs that reflect your philosophy of life. A mindset is usually based on a theory about how the world works.
For example, that the world is getting less safe, that money will make you happy, that everything happens for a reason, or that people cannot change. All of these beliefs have the potential to shape how you interpret experiences and make decisions. When a mindset gets activated — by a memory, a situation you find yourself in, or a remark someone makes — it sets off a cascade of thoughts, emotions, and goals that shape how you respond to life. This, in turn, can influence long-term outcomes, including health, happiness, and even longevity.
— The Upside of Stress (Kelly McGonigal), Loc. 407–12