I have a folder that I drag emails into that are private and confidential. But they are all visible if someone goes into "All Mail."
Is there any way around this?
I really don't understand "labels."
Do you share access to your Google account? No? Then there's nothing to worry about. "All Mail" is simply all your mail.
If you do share access to your Google account, then there's no amount of organizing that will protect your messages. They will always be findable by anyone who can log into the account.