The toggle for showing only unread messages is great, but when you also have folders for organizing teams, it gets very weird.
If you toggle to Show Unread, the folders still show. You only want to find the unread messages, but you might feel like you need to click on the folders. If you do, there's nothing in there (granted, you could look for the unread count number that isn't there). But now that you've clicked on the folders, they'll be alternatively closed and open when you toggle back into Show All mode. Do you see how that causes a bit of a UX mess?
Instead, I'd love to have one of these things happen:
Show Unread view completely removes the folder organization; all teams appear if unread OR
Folders show, but can't be collapsed; all are open in Unread view. OR
Folders default to Open for Show Unread view. This openness state for each folder is different from Show All view. But this option might be a little confusing, too.