This always happens to my little brother. Sometimes it makes sense. One time he brought a book that was so big it was blocking the x ray or something. But other times it’s completely random. This has happened pretty much every time we travel, I even have memories of it happening when he was like 7 years old. He’s an adult now and it still happens.
I’ve made the book mistake a couple of times. When I immigrated to a new country, I had brought along several small carvings and ornaments that I liked to display on my shelves. Each was wrapped carefully in newspaper, but the TSA was not a big fan of that. Went through security at two different airports and had to stand there awkwardly while an agent unwrapped every last item and nodded in amusement over the peculiarness of each one.
Funny enough, I would bring bottles of assorted (mostly non-prescription) pills on each trip and they never batted so much as an eye at those. Could have easily been smuggling in MDMA for the better part of a decade.
