RPPR is the method of understanding a simple but effective method of change. If you can recall the story of the little train that could, this may be helpfull in understanding. In this story there was a little train that approached a giant hill, and as it begain to climb this hill it began to say to it's self, "I think I can.. I think I can... I think I can...". Finding after much effort and work, the little train accomplished climbing the hill.
The key idea is not just in the initial idea of the story but an important event that followed. You see after that little train climb that hill it soon came up against yet another hill. This is where the story somtimes get forgoten as adults, the little train begain its approach and as it did, it did not say to it' self; "I think I can", no, instaed said, "I know I can... I know I can...".
The same easy idea is the essence of RPPB, we may have that dought when we first approach what seems to be a insurmountable, unbelievable, or enormous task or behavior. However, as the train with hard work and effort enormoussly unattainable, undesirable, or enormous tasks or behaviors, may be obtained, achieved.
Have you found yourself telling yourself something like this behavior will never change, I can’t believe I did it again, it’s too difficult, just like the train that had its doubt at first, until once the action/behavior has been initially accomplished or succeeded, the enormous task can not be different/changed. However, once that initial action/behavior has been observed or experienced then just like the train on its second hill, we too will have the understanding that the initial action/behavior is obtainable and repeatable.
Then the repetative process comes into great importance.