"The best way to tell when a thought is lying to you is to put it under close scrutinization. Can you absolutely know for certain that it's true? How do you react when you think that thought? What emotions do you experience? What physical sensations do you experience? If these are negative, the thought is probably a big fat liar. Notice what actions you take based on this thought and outcomes that come from those actions. The outcomes arising out of the thought always prove the original thought, and the vicious cycle perpetuates, leading you to other stressful thoughts.This cycle is why many thoughts attach so tightly. While it's near impossible to let go of these stress causing thoughts, you can learn how to help them to let go of you.When you come to the realization that your thoughts are creating your reality, you'll be on your way."
I just tell my brain to shut up. :)