Now here's the difficulty: most people do not believe they have any choice regarding their thoughts; they believe they have to be thinking whatever thoughts happen to be in their minds at a given moment. I agree that, without training, it is very difficult to exercise such choices. But that's what meditation is for. Consistently bringing the mind back to the meditative support after it wanders or becomes distracted demonstrates to us that we do not have to be taken hostage by what we are inclined to think. Yes, it takes effort. And it is profoundly liberating when we make that effort.
Our best friends and our worst enemies are our thoughts. A thought can do us more good than a doctor or a banker or a faithful friend. It can also do us more harm than a brick.
-- Frank Crane