tl;dr Refraction is absolutely retarded bullshit.

Is it only observable for a small amount of substances? I've been outside using window glass trying to note the effect it has on light shining through, and the only thing window glass does is reflect it. There is no change in the light's path between the presence and absence of glass. The intensity is the only thing that has changed, due to the fact that it is partially reflected from the surface of the glass.I observe the same thing whether the light source is sunlight, laser light or light from a flashlight.

So, what gives?