New York Times science reporter Dennis Overbye clearly loves the near-mystical thrill of experimental physics, but he's aware most people are puzzled by its purpose. (In fact, as the Wire reported here, here, and here, people even feared the world's largest particle collider was designed to bring about the Armageddon.) Overbye explains that the abstract mission of particle physics often doesn't translate:

Sure, there are new particles and abstract symmetries in the offing for those few who speak the language of quantum field theory. But what about the rest of us?
He rattles off a number of inventions that came out of physics theories as side products. But even then, he notes, practical products are not really the point. It's about the thirst for understanding:
They want to know where we all came from, and so do I.
Is that enough to justify billions of dollars of research?