The agent took it a little bit too serious, normally the most important question is who has packed your bags and if anybody had the chance to place any items into your bag, because of obvious reasons...

All other questions might be asked, if the agent likes you or is pretty bored or wants to slow down the process in order to hire more people.

It is mandatory for TATL on US metal ex Europe.

If you fly across the pond quite often, it is as boring as the same questions by US immigration officers again and again...