I personally don't mind my government (US) tracing my whereabouts and my purchases because I don't feel they can use that information against me. Mainly because I do nothing that they would conceive as harmful to them.
I take it that you don't sit too far from the center of the political spectrum. You're probably not a third party supporter (Communist, Green, Libertarian, etc.). You're probably not Muslim. You're probably not gay or lesbian. By your statements, you don't strike me as an activist for social justice or civil liberties. It might surprise you to learn that our country has quite a lot of folks who, for some reason or other, are currently or will eventually be persecuted for being different, holding different political or religious beliefs, or pissing off the wrong elected official. Think about the journalists--what happens when their every move is known in advance? This is a power that the government should not have, not without warrants and the traditional Constitutional protections given to our people by the Bill of Rights.
Head over to Wikipedia and read the article on CAPPS (disclosure: I wrote it a few months ago) and CAPPS II. There are so many problems with this system, besides the big one--it won't work.
In my opinion, the most disheartening aspect of this debacle is that a syndicate of large corporations lied to the public, lied to their customers, and undermined the Constitution. But there will be no reckoning. This is a burning example of our corporate "citizens" escaping responsibility.