This quote really rings true to me. How about you? (It also metaphorically describes the biology of habits and neural pathways.)
“As a single footstep will not make a path on the earth, so a single thought will not make a pathway in the mind. To make a deep physical path, we walk again and again. To make a deep mental path, we must think over and over the kind of thoughts we wish to dominate our lives.” Henry David Thoreau


I like this Laura – thanks! Of course I’d add “and the kind of feelings” – we know that feelings engender feelings; the brain becomes increasingly efficient… if we use it to feel anxious, angry, full of blame, then it becomes better and better at that!
This is a quote that not only I live by but most of my peers live by as well. “Our lives begin to end the day we become silent about things that matter.”
Martin Luther King Jr