I found myself answering to a question of a new user in TeX.se. Actually he said that that was for him a good solution, but since he wasn't use to the functioning of the wheel he did not choose best answer, so now that question is fluctuating in the TeX.se servers as it was a not answered question, which I don't find very good for organising archived problems and opened ones.
It was the very first time for me, but going around the site I found may situations like that, so I guess that it should be make more clear that choosing a best answer is not just a good action for those who answers, in order to give them reputation but, also a necessary practise not to obstuct the whole site with "answered question which appears not to be answered".
This phenomenon in my opinion is also responsible for what I call the well of forgetfulness, or "all the question really without an answer that people don't look anymore since nobody will give them best answer" and also because nobody wants to check question per question which are the ones solved or not.
This problem also should be discussed in the future (tons of question that will be not answered so they should either be closed, cancelled or "brought to new life"), but is not a good use to make more than one question at time
I made the question probably unclear with the last two paragraph in which I introduced another question aside the one about question without BEST anwsers, that is the one with not answered questions, meaning that a question without best answers on stackexchange, although it has answers, itdoes no have a solution, which is probably the term I was looking for.
An answered question without a choosen best answer is an UNSOLVED question, and I guess there is a big need to distinguish the two category, which in most cases are distinguished by the OP of the questions by voting best answers. When they do not select the best answer is clear for me that, even an answered question, in an unsolved question, and so it should be clear for people that search for their own interest or for solving it whether the question is already solved or not.
From this reasoning the necessity of making clear to new users that "choosing a best answer is not just a good action for those who answers, [...] but, also, a necessary practise" (self quote from above), and in the case that the new users find their solution but do not select a best answer the necessity of making clear to anyone who find a certain question whether it has a solution or not.
Jut to clarify further I'm just speaking about answered questions, meaning that is problematica sometimes to understand if there's the need of other answers or not, since TeX.se maybe should also have an encyclopedic function.