Your thoughts influences your action, and your personality is not far from what you think. Although once in while negative thoughts do creep up, the best we should so is to shake it off before it get hold of us. And our thoughts has a lot to do with our well being, health and mindset. We are warned in the bible in Proverbs 4:23 'Keep your heart with all vigilance, for from it flow the springs of life'. Now what is the best way to understand this topic, let assume our heart to be a room, and the condition of our rooms is subject to what we allow inside and how often we keep our room neat. Our hearts, minds, and souls feeds on what we see, listen, read, and think, these are the very things we allow into the room of our conscience. If we are used to a clean room the early we spot dirt, the early we kick it out so it won't bring dirt into the entire room. This is the warning in the biblical passage above. So you must learn to differentiate between what is healthy for your thoughts and take out those ones which are not helpful such as hate, lack of forgiveness, pride, envy etc. Feed on love, be happy, be contented, and always learn from your mistakes, do not forget your CREATOR because from HIM comes help, forgive yourself and also others. Show love to everyone that comes your way, because it is through love we can overcome the dark.