"... life does not consist mainly -- or even largely -- of facts and happenings. It consists mainly of the storm of thoughts that is forever blowing through one's head." -Mark Twain
The lesson: There are two lessons that can be learned from this quote.
One: Be mindful that each one of us awakens each morning and faces an internal battle with our thoughts, feelings and personal desires. Take that into consideration when interacting with other people and realize that their position on a topic or reaction to your opinion is based solely on their perceptions.
Two: Give yourself a break. A lot of what's floating around up there has nothing to do with reality. Focus on the positives, ignore the negatives and if you really want something- stop dreaming about it, set some goals and go get it.