All the wars, all the hatred, all the ignorance in the world come out of being so invested in our opinions. And at bottom, those opinions are merely our efforts to escape the underlying uneasiness of being human, the uneasiness of feeling like we can’t get fixed ground under our feet. So we hold onto our fixed idea of this is how it is and disparage any opposing views. But imagine what the world would be like if we could come to see our likes and dislikes as merely likes and dislikes, and what we take to be intrinsically true as just our personal viewpoint.
Pema Chodron, Living Beautifully with Uncertainty and Change.
A good part of our automatic thinking is negative. Discontent comes naturally to us. Kids are discontented with their parents, parents are discontented with their teenagers, we are all discontented with our weight, and the prevalence of aesthetic surgery points to our discontent with the way we look. It is as if the brain is wired for discontent. With mindfulness we can become aware of this tendency. I remember distinctly the first time I became aware of the habit of negative thinking. I was at a staff meeting in work. All of a sudden, I noticed that I had a negative mental comment about everyone who spoke. Either he was incompetent, or he kept saying the same useless things, or he did not really understand the problem…Then a light bulb went on: Maybe the problems were in my mind rather than out there. Maybe I had a problem accepting things as they are, and people as they are. 
When there’s something in the future that we’ve got to get to, there’s tension. Things start to solidify; flexibility begins to dwindle. When there’s a strong sense of self-consciousness-“I am this, I’m not that; I wasn’t that, I will be this” – then there’s a tightening of one’s energies. When we defend ourselves from people, events, memories, and feelings, when we shut things out there’s tightening and stress. When we try to perform and make ourselves into something, there’s tightening and stress. When we compare and compete, there’s tightening and stress. 
Mindfulbalance 