"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 believe that is totally true. A single act or thought is not really changing anything. It is only when we continue acting and believing can pathways be made. If we think only negative thoughts and criticisms, they will dominate our environment. Think about it... we all know someone who points out the flaws or the weaknesses about almost anything. They do not know how to focus on anything else because that is the dominant thinking in their head. On the other hand, we all know someone who is always positive and cheerful... who tries to find the good in people and situations. They let the positive thinking influence how they see their world and environment.
Which one would you rather?