I learned today that new experiences can activate proteins in the body, and these proteins can code for new genes.
This means that if you put your self in stressful situations, beyond what you think you are capable of, your biology changes. It adapts. Adaptation is what us humans (and every single organism) is about.
When I see someone I admire and think “I can't be like them.” I am correct, but only for that present moment. Currently I'm not like that person, but if I push myself, I will be physiologically and psychologically different.
I have to be willing to leave behind who I am in order to become who I could be. Every challenge then is quite literally an opportunity to grow.