You need to get in the habit of only choosing to think about the thoughts that make you feel good. If you spend all your time thinking about the thoughts that bring on the negative emotions such as anger, fear, pain and sadness then that is all you will be able to feel. You won't be so stressed out all the time if you didn't keep thoughts that stress you out fresh on your mind all the time. You choose how you will feel by the thoughts you choose to think about. Learn to flush the bad thoughts out of your mind and grab on to a good thought and you will smile inside and out, it is your choice.