Almost every freaking test run they have done with TSA in the last 9 years has failed to detect all sorts of weapons, chemicals, bombs etc. Everyone ignores that because it's not put on the front page if it makes it to the news at all. Most of the time they don't publicize their tests or results.
Does that make me feel more afraid. Nope. The terrorists do not need to commit large scale operations anymore. They've accomplished what they wanted and the US (and others) have spent billions of dollars proving it.

I have always wondered if the few people caught in the last few years didn't get caught on purpose. Negative reinforcement to keep the fear level elevated.