ACLU has a nice piece explaining some of the reasoning behind not wanting to have every detail of our lives recorded and scritinized by government authorities.
The most important bit I think comes in answer to the the oft-cited (Vic Toews I’m looking at you) quip about “If you’re not doing anything wrong, you have nothing to hide.” If I have done nothing wrong, why do you need to know?
It turns out that we have a lot of reasons not to want to be subject to government scrutiny. This article lists a few of them.
Plenty to Hide (ACLU)
Plenty to Hide (Lifehacker)