A man is what he thinks about all day long.
Credit: Ralph Waldo Emerson
This is one of my favourite quotes.
When I find my mind wandering to trivial matters or worrying over things I have no power to control, I think of this quote and consciously change what I am thinking about to something of value. The more I do it, the better I get at it.
Oh, by the way, I am sure this applies to women too. Annoying that quotes from even a few years ago are sexist but I think it would be wrong not to use the original words.