Something that I'm sure others have noticed, but that always seems to plague my questions, is the fact that answerers tend to focus on parts of a question that don't actually matter. For example, while I admit my recent question How big can a moon be where you can jump to its planet? suffered from some inconsistencies (escaping the moon vs reaching the planet, I didn't realize at the time that the two were separate), I really don't think it's my fault that the first two answers were about how you can't run in low-gravity. The first paragraph of the question summarized part of the story I was writing, and I wanted to provide some sort of context just to give a possible application of the scenario, but I was in no way married to the concept, and I thought my question did a pretty good job of showing that.
However, it got me thinking: is it actually a bad idea to provide this kind of context? Is it perhaps detrimental to the quality of a question to provide some sort of explanation of why you're asking, or how you will use the answers? Should questions seek to only give the necessary parameters of the question, and leave absolutely everything else out? For instance, maybe I shouldn't have provided the above example.
Or, alternately, is there a good way to separate out world-information from question-information?