The vast majority of Americans have nothing to hide and very little worthwhile information to contribute that would be of any interest to those matters of interest to the NSA. The un-policed surveillance of Americans is not only unecessary, therefore, it is an expensive waste of money and personnel. Instead, the NSA should learn how to focus its efforts on individuals of interest.
The NSA domestic surveillance program arguably violates the civil liberties and constitutional rights of million of Americans. Investigations by members of Congress as well as research by non-partisan, independent organization reveals that the NSA domestic surveillance program has not thwarted terrorism. Therefore, the program encroaches on freedom and liberty and produces not tangible results.
While domestic surveillance seems intrusive, it is safe to say that they are not listening too hard to your personal conversations. They're just trying to find major threats to the safety of this country. With more accessible technology comes more power to find information. If they could use this during the Revolutionary War, they probably would have.
Something that the people seem to forget is that the government has been monitoring us for a very long time. It was only lately that the secret got out. Had we continued to be unaware, no panics or uproars would have ever occurred. Also, the purpose is not to snoop into your business, but to monitor for signs of terrorism and major crime. The entire reason the organization exists is for the protection of the people.