Yeah screwing with the network interface of the machine you're SSHd into is something nearly every sysadmin have done at least once.
That or changing something, rebooting the server and subsequently being unable to contact it again due to said change. I'm always scared and feeling I'm taking a risk when upgrading a major OS version over SSH, yet Ubuntu never failed me in that, it's the silly things that got me, like messing with fstab.
What? Is there some new controversy going on ?