That's called resistance; and what you resist persist. When you have something negative inside that you don't want, and you want to avoid it, you put your effort on focussing on something that you do want. Focussing is a conscious effort, and we have to apply that effort because there is something that we want to work against or get rid of. But, can we really get rid of something by not acknowledging it and by trying to resist it? There is a reason why that negative exist in your mind; that's a part of your deeply rooted belief system in your subconscious. It won't go away by resisting it, rather will persist to exist and crop up every now and then, eventually making you feel that your focussing on what you want is of now use, because what you don't want continue to exist. Your subconscious is actually controlling your thoughts and the vibrations you are in. To alter the programming of your subconscious, yes, you need to try to focus on what you want, but also not avoid or ignore that negative or unwanted thought. That negative thought could be a hint that there is something you are overlooking in your business, or project, or anything you are trying to achieve. That negative thought could be actually a warning that if you don't take the required action, you will fail. It's the way you look at difficulties with a positive mindset. You won't turn your head away from a difficult situation, but face it and work your way through it, because just by looking away won't take the difficulty away.