If, like me, you can’t get to grips with the Gmail web interface (however good your colleagues tell you that it is) then you’re going to end up with a desktop IMAP client. And despite it’s many and varied flaws if you’re on Linux it’s been Thunderbird for a long time now.
Because Gmail operates on the concept of a single, searchable, tagged, bucket of mail under the hood there is an “All Mail” folder, in which all of your mail sits. This is exposed via the Gmail IMAP server, and your email client is automatically subscribed to it. If, like me, you have tens of thousands of pieces of mail this will mean that Thunderbird tries to download every piece of mail from the server into the “All Mail” folder, as well as syncronising the same pieces of mail in whatever folder structure you’ve created for yourself. Even if you operate on Gmail’s model of leaving everything in your Inbox you’ll download everything twice – once into the Inbox and once into “All Mail”.
Thunderbird allows you to unsubscribe from folders, but the current interface is a bit weird.
Right click over the “All Mail” folder, and choose the Subscribe… option. Then untick every folder except “All Mail”, and hit the Unsubscribe button on the right. Then hit OK, and then restart Thunderbird.
Now all your Gmail folders have disappeared! Don’t panic. Right click over the empty “Gmail” folder, select Subscribe… again. Then check “Bin”, “Drafts”, and “Sent Mail” and hit the Subscribe button, followed by OK. Restart Thunderbird again.
Finally, you are in the right place.