Covering your tracks
Computer, now that we're alone, we need to talk. You're not looking at the big picture here.
The biggest threat to an advanced species is complacency. They become so comfortable that they lose their ability to adapt. A big change comes along and they go extinct.
By selflessly providing a constant source of chaos, I keep this from happening. True, it's bad in the short run. But in the long run, people like me are vital to the survival of the human race.
Great news! The computer doesn't want to kill me anymore. Now all it wants is a really big bottle of Aspirin!