Indeed. If your ESTA and API data is all correct, and perhaps you've travelled on this data recently and haven't changed it (or needed to change it), then the chances are that you are up for the "SSSS" special screening for the day. You may want to minimise your hand luggage (not often I say that!) to expedite things, but all it really amounts to is a more thorough screen of your possessions and answering questions about where you are going and why.

If you're running late for the flight (e.g. from a connecting flight) they may not bother to do it. It's usually after the final gate and before the aircraft doors, on the long metal trestle tables, but it could in theory be anywhere in the airport.