And so I installed Mac OS X Mavericks on my work Mac.
This resulted in all my email being deleted in Apple Mail. "No big deal," I thought. "I'll just rebuild my mailboxes from Gmail." Except that's impossible when Apple Mail deleted all your mail off of Gmail.
And so now all my email... absolutely everything... is gone.
Fortunately I was smart enough to make a backup before I started, so I am hoping that I can restore everything... but this is a fucking horrendous situation. Thank you so much Apple for once again releasing a piece of shit OS that's fucked me over. Hard.
UPDATE: Apparently the problem cannot be laid entirely on Apple's doorstep. Gmail uses a highly non-standard form of IMAP, and doesn't really give a shit. They want you to access Gmail from their website or official Gmail client... and with any other method you're just taking your chances. But, again, Apple is not entirely blameless because Gmail is an incredibly popular service, and they shouldn't advertise as being compatible if they really aren't... whether it's their fault or not!
UPDATE UPDATE: In all seriousness, Gmail is the work of the devil. If you are using it with ANY email client not made by Google, including Apple Mail, you should archive your mail and walk away. Immediately. I've just gone back to using my host email for a while, as I know they are using standard IMAP protocols and aren't throttling bandwidth in any way like Google does.