There is an old adage, "There are no stupid questions...." What happens in the ellipsis at the end of that adage varies a lot, but the adage always starts with the same line.
Here is a very simple synopsis of the XY problem:
You want to do X, and you think Y is the best way of doing so. Instead of asking about X, you ask about Y.
On Stack Overflow, there is an overflowing abundance of the XY problem. http://www.perlmonks.org/index.pl?node_id=542341
And there are a collection of people who will willingly and wholeheartedly give an answer to Y, without a thought to what X is.
I am an IRC operator on #python on Freenode. We take the XY problem very very seriously, and outright refuse to give Y answers when it's clear the user should've mentioned X, and we push the programmers who come to us for advice towards proper solutions for their actual problems.
On Stack Overflow, establishing and resolving X problems is hard, while giving a Y answer is a way to instantly receive rep. This is a problem! As a community, we need to think about how to fix this problem. Does anyone have any ideas?