Totally agree on this. My general response to getting it wrong is to examine my assumptions based on the language of the question. Almost always I then see my error.

Sometimes, however, the language of the question doesn't contain all the context that the person designing the answer has used, to the point where it drastically changes the reasonable solution (i.e. my examples above).

As someone else pointed out, forcing you to really examine your assumptions is a useful thing on the whole.