I would say about 80 to 90 percent of people’s thinking is not only repetitive and useless, but because of its dysfunction and often negative nature, much of it is also harmful. Observe your mind and you will know this to be true. It causes a serious leakage of vital energy

I would say about 80 to 90 percent of people’s thinking is not only repetitive and useless, but because of its dysfunction and often negative nature, much of it is also harmful. Observe your mind and you will know this to be true. It causes a serious leakage of vital energy (Eckhart Tolle, The Power of Now: A Guide to Spiritual Enlightenment)