What might be entirely coincidence, but I found interesting, was that this was a JetBlue flight from JFK. The one time I triggered the explosives detection machine was a JetBlue flight from JFK. I had almost nothing special - a carryon I've used many times before, with clothes and toiletries. I also had two small fossils I bought from the Evolution store in NYC, which the TSA agent seemed especially interested in retesting.
In my case though, I just had to deal with a thorough search of the carryon, confusion from other TSA agents (something like "oh, you searched the carryon? That wasn't necessary" from one agent to another) and listening to the main TSA agent wax poetic about how evolution is a lie and how climate change is a hoax.