So far as I can tell, there is nothing to the NSA "scandal" other than it plays to the paranoia/guilty conscious of people so it makes for good press. There have been glitches here and there where computers picked up things they weren't supposed to, but that will improve with time. I believe that the people designing and building that system want it to work in a balanced way, even when the law allows them to be more heavy-handed and intrusive. It is just going to take a lot of work to do that. There are some truly evil people in this world, and if this is what we as a society must do to stop them, then so be it.
The stop and frisk thing is a little more troublesome. I can see how it can become oppressive harassment in some high-patrol areas, but, at the same time, I also believe that the police should be able to take reasonable steps to protect themselves. They have families to go home to as well, and people who love them, and lives that are ruined every time one of them is seriously injured or killed. I could never be a police officer. I am too trusting of strangers and will give them the benefit of the doubt usually. That is the thing that will get you killed. I do truly believe that the majority of police officers--the very vast majority--are decent people. They just may not always deal with the stress and pressure of their jobs so well, and transfer that negativity onto others. It is human nature.