It took me 90 minutes to get through TSA in LAX recently. It split into two lines and the side I chose was moving sooo slowly compared to the other line. The person checking ID's was making small talk with every single person before letting them move along.
Briefly chatting with someone is a good way to pick up on whether they're relaxed and behaving normally or tense and secretive. It's probably a far more useful security measure than checking shoes or limiting liquids.
