I have trouble relaxing. I am intense and serious. I put a high premium on learning and growth. Of late, I have been rethinking 'Learning' and 'Growth' and each one's relationship to Wisdom. Four-and-a-half centuries ago Michel de Montaigne said - "But just look at him after he has spent some fifteen or sixteen years studying: nothing could be more unsuited for employment. The only improvement you can see is that his Latin and Greek have made him more conceited and more arrogant than when he left home. He ought to have brought back a fuller soul; he brings back a swollen one; instead of making it weightier he has merely blown wind into it."
An Ego inflated with the knowledge of knowledge (or the delusion of knowledge) is not the same as a Soul nourished and strengthened with the essence of knowledge. Sometimes it is difficult to tell the difference, especially within ourselves; and sometimes it is a quality or characteristic that we too easily or quickly judge in others, giving them too much credit or too much blame.
Perhaps part of Wisdom involves recognition that the ebb and flow of situational circumstances beyond our control has as great an impact (or a greater impact) on success, failure, power, and perceived knowledge as does the individual attributes of intelligence, creativity, and the ability to communicate persuasively.
To approach Happiness one must first seek Truth and Wisdom; and when one realizes that Truth and Wisdom, (like Happiness), are unattainable ideals, one must utilize the aforementioned individual attributes (intelligence, creativity, and the ability to communicate persuasively) along with acceptance, humility, resilience, and persistence to incrementally assist and encourage both oneself and others. And as we approach these ideals and occasionally glimpse the distant peak, one must also appreciate the process. This is the task at which I often fail.
We have been given our humanity in order to experience Life. It can be discouraging to realize that we will not reach a pinnacle (in this lifetime?), yet still we must climb; but then as we climb we sometimes fail to notice (much less account for) the breathtaking view and the exhilaration of the experience. When I even notice these things I am often inclined to treat the beauty and joy of my day-to-day existence as simply a means to an end instead of as an end unto itself. I should better balance my inward/upward (intransitive) contemplation with my outward (transitive) contemplation.
Perhaps this is what Montaigne is referring to when he is critical of a swollen Soul. Perhaps the warning is to not take yourself too seriously; or at least to stop / slow down every now and then and smell the french fries. A warning I should heed and an experience I should occasionally enjoy.
... Yet I would still maintain that it is better to err on the side of 'too serious' than it is to languish in the land of 'lighthearted'.