Why keep thoughts positive?

Why keep thoughts positive? I will try to explain this without getting too deep on the subject.We are all inter-connected in life.Though some are visible,some are not visible to the naked eye.See it as a web......every interaction you have encountered....every relative...every friend/work colleague....every action.....EVERY THOUGHT.yes that's right every thought! Now as you have a negative thought,that then vibrates the web and anyone connected to that line on the web will feel the lower vibration.say you had negative thoughts about a person....that person would feel something has changed or something is wrong.Have you ever felt off and had no idea why? chances are something or someone was directing negativity towards you. Now if we turn that around to positive thinking.We then vibrate at a higher frequency....the ones connected on that line of web will instead of feeling low vibration....feel the lift in Vibration.....feel the happiness....feel the love...feel the laughter.So you can see how your thoughts can shape your reality and that is why "Do not worry" and "Do not anger" are very very important.Thoughts have a snowball effect on your life.....so if you only do one thing today....change your thinking to a positive one.