[elihu]

I guess the internal reflection bit explains why less total light energy might escape; if it hits the shirt and bounces off the water-air boundary and hits the shirt again, then it had two chances to get absorbed by the shirt instead of one.

But yes, you're right that shiny things tend to seem darker from most angles, because the observer is usually not in line with most of the reflected light.

In computer graphics, Blinn highlights are a pretty decent approximation for shiny surfaces. (Interestingly, the highlights generally don't take on the color of the object unless it's metallic.)

https://en.wikipedia.org/wiki/Blinn%E2%80%93Phong_reflection...

Car headlights on wet pavement are kind of a worst case. You don't get much benefit from your own lights because the vast majority reflects off at a useless angle, but it does reflect back up at oncoming traffic.

(Impractical startup idea: headlight drones, that fly ahead of your car in rainy weather and illuminate the road in front of you from a more useful angle. Powered by microwaves beamed from the car.)