If you refresh the CAPTCHA beneath a post you're entering because you can't figure it out, the refresh erases your post. Since you're not likely to enter/refresh the CAPTCHA until after you've completed (but, of course, not submitted) your post, you're screwed and have to re-enter it. Fortunately, I'd made a copy of mine out of habit, but it would be much friendlier to preserve a post when refreshing.