When you first setup a droplet if you added a ssh public key to the server in order to log in to the server you must use ssh-add <path-to-key> in order to log in as root. However if I create a new user, and dump that same key (or even a different one) into it's authorized_keys file then I am able to ssh in directly to that new user without using ssh-add. Can someone explain to me why I can log into one but not the other without using ssh-add?