So, when I reply to a post and then decide my ramblings aren't worth anyone's time, the stuff I typed as well as the original quoted post hang around. For example, when I then go to reply to a different post, the stuff I cut is back and included in my new post. Is there a way to prevent this from happening?
Delete all the contents of the text box at the bottom of the page before you click reply or whatever is in there will be added to your post
Click the little floppy disk button and it gives you options to Save Draft and Delete Draft. When you realize that you narrowly escaped saying something stupid, select Delete Draft and then navigate away.
If the draft is saved server-side then there isn't anything you can do. EDIT: Just cleared the cache and re-logged in. It's definitely saved server side.