Thoughts are way more powerful than what we think, lot of people tend to think that thoughts have no power and that they're free to think whatever they want and it will not affect their life, in fact, it will affect their life dramatically.
Thoughts play a very big role in our life, we think before we do, thoughts might not affect our immediate actions, even though in most cases they do, but they will definitely affect future actions, therefore be cautious of what you think of, it does affect your mood, your focus and your achievements in life.
I tend to think of negative thoughts as a devil or an enemy, trying to bring me down, and I fight it with all my power, I refuse to accept that it's part of me and I abandon them by distracting myself every time they appear in my mind by an immediate action around me, or a different thought, in most cases if you keep yourself busy there wouldn't be much place for negative thoughts but even when they do focus your sight on something that is happening around you and question something about it, it will take your focus immediately off the negative thought since the brain is only capable of holding one thought at a time.
Careful driving that car inside of you! Focus on the positive things around:)