As one gets along with time in life, many thing accumulate in the brain. You cannot recall them explicitly. But it is all there. Therefrom come life's many blessings, like the growing personality and the nostalgic memories. On the other hand, like a wine that has gone bad due to an ill conceived maturation treatment, traces of the past can kill the vital freshness within the self.
Therefore it is sometimes good to forget. To feel as if one was born today, where everything in the world is fresh, envigorating, and full of surprises. To feel again that everything is possible, where you are provided with potentially infinite future time. You felt like that in your childhood. There is no reason why you cannot feel the same, no matter how old you are. It is just a matter of tricking your brain into an exquisite cocktail of context-formation, pretending, and believing in the potential of the universal elan vital. Everything is bottomless, and therefore infinite.