Positive lies are based on the way how you want yourself to be. This is how you tune your subconscious mind and soon this becomes a habit. The good thing is that as this is a habit, you achieve that you lied yourself about
Negative lies are the ones where you just can not take blame of your mistakes. You will find every reason to blame someone for what went wrong with your life or for where you are today. It is very easy to do this as takes all responsibility off your back (you feel this way).
Important is to know what type of a liar are you?