As a Buddhist, I approach this story in a very different way. First, if one lives in the present, free of ego, and mindful, the glass is always full. We understand that regardless the circumstances, our true Buddha nature is always at peace and content. We and are lives are perfect as they are; there is nothing that we are lacking that needs improvement. We live in a state of equanimity, both towards ourselves and the world around us because we truly accept our lives and the world as it is right now and we love ourselves unconditionally and have compassion for ourselves. We have no unskillful desires, no cravings.
As I’ve said elsewhere, both in this blog and in my books, this does not mean that Buddhists are static slug-a-bugs. As functioning lay persons we must do a certain amount of thinking about the future, whether it involves our work, our relationships, our education, whatever. While we live in the present, we must chart a course for the future, especially when we are young. (How a buddhist plans for the future yet remains present is a topic for another blog posting and a chapter in my book, Making Your Way in Life as a Buddhist.)
Second, this is not a matter of perspective ... it is for a Buddhist better put a matter of a lack of perspective. The Buddha dharma says that all our perceptions are illusory and that all things are impermanent and changeable. Through our practice we come to understand the truth of the emptiness of all five skandhas (appearance of form, feelings, perceptions, mental formations, and consciousness-ego) ... that they are all of dependent origination, have no intrinsic existence ... and so we are able to see things directly, without the intervention of thought, without a perspective.
Now obviously, most of us are not at the stage of our practice where we are either enlightened or in a state that approaches enlightenment. We could therefore not say yes to all the assumptions I’ve stated. Perhaps much of the time, but not 24/7. And so we have moments, or many moments, where our ego rises to the fore and we look at the glass as being half full or half empty.
But hopefully when that happens, we have the ability to stop, to focus on our breathing, and to be aware of our ego rising, and rather than engaging it or giving in to its pull, watching it subside. Because we know, not yet instinctively deep inside perhaps, but at least intellectually, that the glass is indeed full. We have learned to discern the difference between the voice of our ego and the voice of our true Buddha nature. There is nothing that we lack.
Another lesson in practical Buddhism.