Anil says only shiny things, a mirror or still water, reflect light; a rough plaster wall does not

Why

Anil is drawing a line most people draw: a mirror clearly reflects, a wall clearly does not 'shine', so reflection feels like a special property of smooth things. But the only reason you can see the wall at all is that it throws light back into your eyes; a surface that absorbed every ray would look pure black. The difference is neatness. A mirror is smooth enough that parallel rays stay parallel after bouncing, so you get a sharp image. A rough wall scatters each ray a different way, so there is no image, just light leaving it in all directions, which is exactly what lets everyone in the room see the wall from wherever they stand. Test: in a dark room shine a torch at a wall and the whole room lightens as the wall spreads that light around. Suneeta is right: rough surfaces reflect too, just messily.