To me good stories are half-n-half: the writer provides half, the words written on the page. A good writer carefully leaves the other half, `the lines between' open for the reader to fulfill. Again if the writer does a good job, the reader will probably fall roughly into a bell-curve distribution, with most of them identifying with the `main direction/theme' of the work (which may sometimes not quite be what the author intended!)

But there will always be some folks that are on the long tail of the interpretation distribution; that's life. The difficulty comes when your reader response is all over the map, or all clumped over in left field when you expected them to be, er, mebbe a sports analogy wasn't such a good idea---what do you call home base again?

Though with a long time beta you'd expect hir response to be in the middle, which is I think flummoxed this guy so much...but people can and do surprise you. Even ones you've known a long time.