Suppose someone asks a question on Stack Overflow, and after posting and working on the problem some more that person realizes there actually was not a problem at all but it was only their misunderstanding or lack of attention.
So, what should they do then? Deleting a question might ban them from asking a question again for some time. Also, when another user who wants to give an answer asks for details, what should the OP reply if there was no problem at all?