Positive Thinking

"We are shaped by our thoughts; we become what we think." Buddha

Long ago Buddha said we become our thoughts, and now science is telling us the same thing.  Most people have repetitive, negative thoughts -- and they become rigid, negative people.  Sometimes a person can look at someone with an illness, and realize why that particular illness visited that person.  Sometimes it is because of unconscious beliefs that we have inherited from somewhere in our family's genetic code.  Sometimes it is our own mindset.  Since so many things point to the fact that we become our thoughts, isn't it a good idea to have our thoughts be good ones?