Lately I have been noticing a phenomenon where a user asks a question which is beyond their ability to understand. It becomes apparent when, for example, someone posts a totally reasonable answer and the OP comments that they don't understand the response, or that the response is confusing when it appears to be clearly worded.
This is difficult because it is sometimes hard to determine the level of rigor and explanation a user is requesting. For a specific example, I saw a question lately which asked for a proof to show that a function is surjective. A user posted an answer, but the original poster complained that the answer was overly confusing, when it probably wasn't, as long as the poster knew some basic facts about surjectivity.
What should we do in these cases? It seems unfair to just close the question, and it also seems unfair to expect anyone to write a lecture worth of information.