[CentOS] Why Kudzu, Why?

So I have a CentOS 5 machine, which I recently did a 'yum update' on. Everything went fine, but I rebooted as a precaution (just to confront any problems which might arise the first time after an update).

And sure enough, when the machine came back up, the network didn't work. Luckilly, someone said (and I quote) 'mv /etc/sysconfig/networking-scripts/ifcfg-eth0.bak /etc/sysconfig/networking-scripts/ifcfg-eth0 and blame kudzu'...

So, what did I do wrong, or what should I have done differently? What's the reasoning behind this? I'll bet there is some rationale, and I'd like to understand it.

Thanks,

Mike