This is absolutely not so. Just because one flies high one day does not mean if you fly low the next day that it is negative at all. Because hey - you are FLYING! There are different joys in all levels of flight (or to leave the analogy, of life). Additionally IF one does have an exceptionally negative day, it can be used to even more appreciate the exceptionally happy days. And another way to understand this is that the happy times, if truly pure and happy, never lose the positive buoyancy they shed on the rest of your days; so in that way those days have raised your overall abundance of life.