That stupid listing on the left is incredibly annoying. Every PM you've ever sent or received in the history of forever sits there with no way to do anything about it.
My list is so freaking long that two things happen. 1) The scroll feature is borked so it bounces back to the top before I can even finish scrolling down all the way. 2) Even when I manage to get through the whole thing, new PM's may not even show up with the unread bubble. People in my guild or in other chats have to literally tell me they sent a PM or sometimes I would not even know it was there.
So I have an idea for the devs. Let us delete these old PM's which will clear up storage used and you can then use that to increase the rune limit higher than 500. Bwahahaha!