When I was a student, I was told (in the mandatory philosophy course) that philosophy is a study of "the most general laws governing the universe". This was, of course, incorrect. What is philosophy, then?
I tried to read some books in philosophy. I tried Plato, Spinoza, and Hegel. I also tried other authors. But most often I could not really understand what they were saying ("To be object for the subject and to be our representation or mental picture are one and the same. All our representations are objects for the subject, and all objects of the subject are our representations") - or it was patently absurd ("The third aspect of the principle is concerned with being in space and time, and shows that the existence of one relation inevitably implies the other, thus that the equality of the angles of a triangle necessarily implies the equality of its sides and vice versa").
It was odd to me that philosophers spent so many centuries discussing some supposedly deep and basic questions, such as "can one really know something" or "does multitude exist", and they still don't seem to have any definite answers. I couldn't figure out what philosophers were actually doing.
I have now arrived to a revised understanding of what philosophy actually is and why it is like that.
Philosophy is the art of discussing extremely vague and abstract questions in such a way that the contemporary (and sufficiently educated) audience feels psychologically convinced that these discussions provide meaningful answers to those questions.
So first, philosophers should be able to come up with a large set of abstract questions; that is to say, questions whose formulation is sufficiently vague and general so that any answers to these questions can never be tested in or applied to any practical matter.
Here are some such questions:
Is it possible that a multitude exists, or are all things just manifestations of one thing that really exists? (Zeno)
Does justice exist? (Socrates)
Can an actually infinite number of things exist, or only a finite number of things can exist? (Thomas Aquinas)
Is it necessary that God exists, and what properties does God then necessarily have? (Spinoza)
Is there some knowledge that we can be certain of, a priori, without having any experience? (Kant)
Second, philosophers should be able to come up with long discussions of these questions, showing an appearance of a reasoned, logical thinking. However, the purpose of these discussions is not to obtain a definite answer to these abstract questions. This is impossible, since the questions are, at best, ill-posed - and often meaningless. The impossibility of actually answering the philosopher's questions is demonstrated by the whole history of the philosophical endeavor. After literally thousands of years of thinking and discussing, the philosophers have never obtained any definite answers to any of their "deep" questions. Each new school of philosophy "reinterprets" the same questions in a different way, and every 50 years or so a "new interpretation" of St. Augustine or Aristotle or Hegel can be published. This evidence shows that the philosophical questions are so vaguely formulated and ill-posed, and at the same time so far removed from any practical experience, that it is safe to say that they cannot really be answered.
It is also safe to say that philosophers are well aware of this fact. Therefore, the purpose of philosophical discussions is not to actually and finally resolve the philosophical questions, but to talk in a way that seems intellectually convincing to people. In other words, philosophers learn how to rephrase the questions this way or that way, citing one or another example from real life, replying to this or that objection that "comes to mind", so that it appears that they obtain an answer to the question.
Of course, when you take an abstract question ("is change possible?") and rephrase it ("can one property of an object change?"), you actually define a new question. Each time you cite an example from real life ("can a whole glass change into a broken glass?"), you begin discussing just that example, - you are not discussing your original abstract question any longer. However, the rhetoric art of a philosopher must be such that the audience is convinced that the discussion makes sense. This is achieved by a judicious choice of words and phrases. So philosophy is, to a large part, a literary and a rhetoric art of written texts.
For this reason, it is extremely important for philosophers to cite other philosophers precisely, word for word, sometimes even borrowing words from another language rather than risk introducing an "approximate" translation. If you use a wrong word, you will not achieve the same impression on your audience.
Why are philosophers appreciated? My hypothesis is that the human brain, developed for particular tasks, has nevertheless the ability to think abstractly, and tends to direct this abstract thinking to imaginary questions, to questions that have no relevance to any practical activity or any experience. In other words, the brain is sometimes prone to idle thoughts about questions that cannot be tested in any way because they are too abstract and general. ("How can an arrow move at all, if the arrow is motionless at every instant?" - Zeno.) When our mind is focused on such abstract matters, our practical experience cannot provide a reliable guidance about what questions are at all reasonable. Our practical experience cannot keep us from asking an ill-posed abstract question, or a question that sounds reasonable and "deep" but actually has no meaning at all. ("If being and becoming are stages of development, what is it that develops or is developed?" - Hegel.) Questions like that are little more than a wordplay. But this wordplay is also a necessary part of the philosopher's craft.
Of course, philosophers do not necessarily tell you that they are merely producing a subjectively convincing text about ill-defined topics. A philosopher might claim that their philosophy actually is "objectively true", or "the scientific picture of history," or "that and only that which can be said without doubt." If such phrases are convincing to their intended audience, philosophers will use them. If other phrases are convincing ("what I am telling you is the ultimate artist's surreal vision of reality, because this vision alone is real") - philosophers will use those phrases. The choice of convincing words is necessarily a function of the epoch, the local culture, and the language used.
So, when an idle person is thinking about such questions, it is in the nature of the human brain to believe that a discussion of these questions is meaningful and important. Here comes a philosopher and gives a long and reasoned discussion that is designed to be intellectually convincing. The person listens to this discussion and feels a certain intellectual satisfation. This is why philosophers are appreciated.
To summarize: Philosopher's work consists of documenting the patterns of idle and ill-directed thought, as manifested in a particular language and culture among the highly educated.