Why do my outgoing messages appear in the UNREAD folder.

Why do my outgoing messages appear in the UNREAD folder.  It’s illogical.  Of course I’ve read it - I wrote it.  

It is confusing and takes up ‘space’ in the unread folder real estate.

Hello Ali,
that is not the designed behaviour of the program.
What mail account does this happen on? Is it IMAP/POP/Exchange?
Do you have any rules set up that could cause this?

Regards,
Olivia