When you hit Save Draft and you get this message:
WordPress Failure Notice: Your attempt to edit this post has failed. Please try again.
Luckily for me, when I hit the Back button I discovered that WordPress had auto-saved the draft and none of my edits were lost.
Still, perhaps they should consider using a slightly less severe tone. Failure Notice is a bit harsh, don’t you think? Doesn’t seem to fit with the WordPress brand, and it certainly didn’t make me feel very good!