But Gmail doesn't have "folders". They have "labels". I wont go into all the details about how Gmail labels work that frustrate and annoy me, but the point is that IMAP clients cannot see labels, they can't replicate it on the client end, etc.

This caused a legitimate problem at work when the finance dept. wants to use this service that reads emails to automatically scan invoices into their system and whatnot. They wanted to be able to only have a subfolder automatically imported into the program, because too many of the emails were not relevant to get imported, creating more work to clear them out.

We were not able to achieve a solution with a simple folder for the users to move emails into to get them imported. Instead, we had to set up a second email account specifically for this importing service, and whenever finance wants something imported, they forward the email to that second account.