My supervisor at work and the rest of her family had to go to a first passport interview. It is something all new passport applicants must do for an adult passport but only if you have never had a child's one
It was all very simple, nothing untoward happened. She was asked where she worked, her DOB, and other questions just to confirm what she had put on her application form
Her husband was asked the same sort of questions with slight variations - he was asked one sons DOB and she was asked the others sort of thing