For most people, when they are very young, a significant part of their personality wants to be older, for they see older people, though not really old people, as having more freedom and of being in control of their lives. Later on, as they get closer to adult age, they may yearn deeply to be 18, or in America, in many cases, to be 21, so that they are truly their own person, an adult, and they eagerly embrace such.
At some point, though, many adults begin to see time as being not so much their friend, but rather their enemy; perhaps, because they have not achieved as much as they would have liked, or perhaps because their physical looks or strength have begun to fade or that they perceive that they are fading, or perhaps because they really love their life as it is, right now, and do not want to lose what they already possess, to the unfairness of old age and mortality; yet, they will.
While, it's true that a significant amount of adults spend inordinate amounts of money on cosmetic surgeries of all types, or diets, or makeup, or this or that, all in the somewhat vain hope that this, somehow, will push time back, most of these adults in their more honest moments, recognize that while taking care of one's health, and one's physical body and one's looks has its place, it is not possible for somebody that is middle aged or older, to look as they did when they were just young adults.
All of this basically means, that time is very real, and further that time always and inexorably marches forward, so that, it would probably be more productive as well as being more sensible to recognize that life has its cycles, and that within that cycle, the inevitably of growing old and eventually dying, are part and parcel of what life really represents. This thus means that rather than pretending or trying to fool ourselves that our bodies are immortal, it is important to consciously recognize, what we intuitively know, that they are mortal, and that our time upon this earth is finite. Therefore it would logically follow that if more people were in tune with the fact that their life goes through stages of which the final stage is the death of that body, they would probably be more cognizant that their time should be utilized in a manner in which what they say or do, is in accordance to being of benefit for themselves as well as for others.
After all, for most people to establish a good career as well as to establish a good family, such usually necessitates having a plan, worthwhile goals, and the wherewithal to put forth the effort to accomplish these specific things. This signifies that in knowing that our time here is limited, as well as recognizing that the stages of our lives are bounded within that time, it behooves us to therefore to be productive and positive in all that we do and accomplished; for all the errors, wrongs, and mistakes that we make, aren't necessarily going to be able to be successfully rectified, because time itself cannot be erased, but instead must be dealt with as it is. So it can be said that in the knowing of the end, from our beginning, our lives will be more meaningful, it we never lose sight of that fact, and thereby live our lives accordingly.