This reporter interviews a number of passengers, and also has some helpful info. For example, she points out that people get to the airport 3 hours early in Israel so they don't miss their flight. Passenger see this as a gateway for racial profiling - a concern that I suspect is fairly widespread in the US, regardless of whether it turns out that way (and I think that there can be no doubt that at least some TSA agents are bigoted). The author also gives us the price-tag for the SPOT training: $600 per agent.
Don't forget that in this country we supposedly have a right to remain silent. Try exercising that right with a TSA agent and see if you make your flight!