If like me you enjoy laboring over long, flowery replies and tweaking them until they're just right, something fucky happens with the formatting if you fiddle with your message too much. When you go to post/preview your message, a chunk is missing from the bottom, and in its place is a load of underscores or something, and a bunch of [size] close tags. S'pose I should have grabbed a screen cap the last time it happened.. will post one up if it happens again.
The reply box occasionally does other weird things, like if you add in a blank line but later remove it, all the text below shrinks.