For a while now I've been leaving my work computer on 24/7 and remoting in to do all my work when I'm out in the world. I have the same public key on both machines (perhaps not the safest thing in the world, true), so I was confused by why I needed to enter my password every time I logged in to my work computer. Not so confused that I took the time to figure it out until recently.
I had set permissions on the
authorized_keys file to 400, but for some reason it needs to be 600.