Why do people break into cars for nothing?

Someon broke into my car last night. This person took the time to coat hanger my lock through a small crack in the window. Got in and took my math book and calculator all my math notes. Took my car ins info my birth control and a hoodie. Why even bother what use is that stuff to them? The only real monetary things they stole were an i pod and the one dollar bill in my ash tray. I just dont get it. I know i feel invaded, but all the stuff they took was useless to them. How do i make myself feel better today?