You probably should keep doing it just cause it is the right thing to do. People are just dumb sometimes. Although depending on where you were and what time it was when the cup was thrown at you, it's possible that guy was drunk.

I used to have a car with lights so dim, that just about any other source of light would drown out my lights. So in a city they were worthless for me as a driver, and only helpful on a country road or empty highway. And I definitely forgot to turn them on sometimes and I couldn't tell they were off because I couldn't see a difference. And then I'd get flashed at. It would always take a couple times for me to realize I needed to turn on my lights. Although for reference this was when I was in school, and I was in upstate New York then. Not here.