Well, Roy, your friend was right to cower in terror at my ogre-like powers of withering linguistic judgment. As someone who never makes mistakes, and as someone who accepts only professionally edited, error-free emails, I probably would have ended up chasing him through the streets trying to stab him with a red pen.
But seriously, folks. The unfortunate thing here, aside from the image of me as a slobbering monster with fangs and an overbite, is that someone thinks his errors would stand out.
On the contrary, the feeling of being singularly and shamefully inadequate in the grammar department is more like an epidemic. It seems everyone I talk to has an irrational fear that he or she has somehow missed a lesson everyone else got and that this person must, at all costs, conceal the ignorance from the grammar-enlightened masses.
The truth is, if you feel you're all alone in this realm, that's your guarantee that you're not alone.
Let's consider our anonymous friend's question: Because you can refer to "a closed door," you can also use the term "an opened door." So far, so good. But can we extend that to the forms without the D ending? Setting aside the form of "close" that rhymes with "dose" and means "nearby" (which is essentially a different word), it's true you can't really have a "close door." So does that mean you can't have an "open door"?
No. In fact, both open and opened can modify the noun "door," even though their corresponding antonyms may not work the same way.