One of the nice features of the iPhone is that it can be pulled from its cradle at any point. You don't have to disconnect it via software or cancel the sync or anything. Just pull it out and use it.
Well, today I needed to use my iPhone and it was halfway through a sync but I figured, hey, what the hell. But, not being totally trusting, however, I cancelled the sync before pulling it out of the cradle.
The phone snapped into action right away but my computer started acting really sluggish. I checked Activity Viewer and lo and behold, iTunes, iChat, Mail and SystemUIServer had crashed. I decided to restart.
After logging in I started iChat up and it presented me with the "Welcome to iChat" panel. I got a little nervous. I gave it info again and when it logged in, all my contacts were missing their nice names. Shit. I checked Address Book—blank. All totally blank.
I tried the trick Kevin mentioned on the Blue Flavor blog and found that my AddressBook.data.previous file was also blank. All gone. The crash erased my contacts entirely, and the backup file. Now I have to go restore them from my offline backups.
Just be careful when removing your iPhone mid-sync, even after canceling. Bad things can apparently happen.
Update: Then, all of a sudden, out of nowhere, my contacts reappear! I have Address Book open and it's blank and I'm writing this and then, poof, it just fills itself in. What in the name of holy fuck is happening here?