What you avoid becomes hard, what you do becomes simple
Have you heard of myelin?
It’s a fat that insulates synapses in the brain, optimizing the circuits that govern any action or thought we have.
Myelin is accumulated through repetition of a specific skill. The more an area of the brain is stimulated and challenge, the more myelin optimizes it.
So the more you do something, the better you become at it (if you practice well). It becomes easy.
The less you do something, the less optimal you are at it. It becomes hard.
It works for anything you do and think.
The more you think about yourself in positive terms, the easier it is to see yourself in positive light. Same goes for the negative.
The more you think you can grow in any area of your life, the more you believe it, the more it becomes reality. Again, same true for the reverse.