As soon as the caveman progressed to the point where he ceased living in terror of the animals, the weather and all the gods, he started thinking about his life and what it meant.
Since the conception of language and the thousands of technical refinements that brought us to the printed page, mankind has written much about this mysterious force. It is interesting to note that "life" has 44 definitions -- one of the most defined words in the world. Here are some of these definitions.
Optimists have defined life as good because it gives most of us something to do. Some people with rosy glasses consider it is a road that is smoothed by the friendships we make along the way. Another person said that living is at its happiest stage when your children have grown to the age when you no longer have to pretend you know everything. A twist of that same thought is that it is something that really doesn't begin at conception -- it begins when the last kid leaves home and the dog dies. A more religious way of viewing our daily life is that it is the only treasure a man possesses; those who do not love it do not deserve it. On the other hand, you can look at it as something too important to talk seriously about, or too important a subject to be taken seriously.
On the other hand, we have the pessimists view of life's dark side. For example, life might be considered a sexually transmitted disease -- which is 100% fatal. Or, is a process with three problems: you can't win, you can't get even, and -- worst of all -- the law now says you can't even quit the game! Or, taking the simpler view, it is just one damned thing after another. You can also take the broad view as the pessimist sees it: exactly like a broken pencil -- pointless.
The scientists have their view too. Dark popular psychology sees life as a two-stage process -- where the first half is ruined by our parents and the second by our children. After "one of those days," a parent might look at living as a constant struggle to make ends meet -- it starts at birth with a baby's effort to get his toes in his mouth. Grim sociologists consider this process as a maze in which there are found many more wrong turns than there are right ones. Computer scientists consider life as a process which would be so simple if only someone could find the manual.
Of course, you can well look at life as a continuous learning process. How about considering life as a grindstone. Whether it grinds you down or polishes you up, depends upon what you're made...