When I was a young astrophysics grad student, I'd return home a couple of times a year. Eating dinner with some of my extended family, one of my great aunts would invariably ask why, at age 28, I was still in school.
I'd tell her about my work studying the evolution of stars — how they're born, how they die. But no matter how poetic or uplifting I tried to make my explanations, she'd always bring the conversation to an abrupt halt with the same question: "So what's it good for?"
Then they launched the Hubble Space Telescope.