Firefox Doesn't Like Full Disks
Firefox (Debian Iceweasel) has been getting very angry with me recently on my amd64 box. Occassionally a restart of the browser would clear it, but when it didn't, I fired up
strace, and finally saw the reason -- strace showed the errors that Firefox was experiencing while trying to write the cookies database to disk. Once I cleared some disk, it's working great. It's too bad it couldn't have shown me that error itself.