I have just been looking through the unanswered questions. There are a number of questions there that are incapable of a simple answer. There are also questions relating to previous questions, which is getting away from the simple question and answer format that I thought that this site was trying to keep.
One type of question that I particularly dislike is: "Is there a word for?", or "What is the word for?"
Often there is no simple word to answer the question.
I could find lots of examples among the unanswered questions. One reason why these questions are unanswered is because they were not formulated very well in the first place.