Full-time system administration is a delicate balance between proactiveness and laziness.
No, I don't think proactiveness is a word, but it is now.
On one hand, you want be one step ahead of the game, always watching and tweaking your systems. On the other hand, you want to write scripts and cron jobs and such to take care of these things for you. Any inbalance leads to either 80 hour hell weeks or 35 hour boredom-filled drool fests (varies depending on what games you have installed). Now, I like to keep my idle time around 20% in case those cycles are needed in an emergency, but it's slowly slipping into the 30-40% range.
Then again, that idle time has given me the time to write a book and hack on various projects, so I guess I shouldn't complain. I guess I just long for some new servers to play with.