The thoughts you have will determined the kind of decisions which you will be making , it means your thoughts have a powerful influence over your decisions and so the wrong thoughts can lead to the wrong decisions same way the right thoughts can lead to the right decisions.
You have to ensure that you do not allow negative thoughts if you really want to keep making the best decisions in life , negative thoughts will not give you the right power to make the best decisions , you should learn to fill your mind with positive thoughts, fill it with thoughts that will add value to your life , not thoughts that will ruin your life or try to ruin your life..
Do you know that many people became depressed because of the kind of thoughts they have , the thoughts led to the depression , the depression did not just happen overnight for many people, it grew from negative thoughts to negative feelings which then led to depression...
So staying away from negative thoughts is a powerful decision which will help you to be able to stay away from depression or prevent you from experiencing depression.
Infact avoiding negative thoughts will make most of your emotional problems to be half solved at least , it will make you to be able to avoid psychological problems that might want to ruin your mental health..
You laugh, you cry, you enjoy and you don't enjoy. There is no way that these things come in alteration. They happen. You cannot avoid thoughts, no matter which state you are in. Try it and you will find it impossible.
Thoughts just come in all forms and colors. You can try to learn to let go of them in an instant.
If you cut yourself with a knife and it bleeds you do not avoid the pain. You may cry or swear, shout or grind your teeth but you feel pain nevertheless. There is nothing to avoid. But if you cut yourself and you took care of the wound and the blood already got dry but you still curse the "damn knife" and that "stupid neighbor wo played loud music and because of him you were not able to concentrate ..." then you stick to your thoughts and nothing but thoughts. It's irrelevant if these are "negative" or "positive". The moment is long gone when you cut yourself.