Hmmm... in the past all my emails in gmail just stayed in my "In Box" in the web interface. Even when I deleted them from Mail.app. So I guess until yesterday I did have some 7,000 emails, all read by the way, in my web interface 'In Box'.
I did not mess with any IMAP paths or settings.
I had IMAP set up before, and its weird that things are changing now. Maybe I'm just unlucky over all. At least now, for some reason, I was able to get all the 7,000 emails in my Mail.app 'In Box' to go away. No idea why they wouldn't the other night.