The Perfect Bounce
Most things, like a wall or a shirt, have bumpy surfaces that scatter light in every direction. A mirror is coated with a very thin, incredibly smooth layer of silver or aluminum. Because it is so flat, light bounces off it perfectly, like a ball bouncing off a smooth floor.
The Stamp Effect
A mirror reflects light exactly as it receives it. If you point a finger at the mirror, the reflection points right back at you. This 'front-to-back' reversal is what makes your right side appear on the left side of the reflection—it’s just like pressing a wet ink stamp onto a piece of paper.
Virtual Reality
When you look into a mirror, you are seeing a 'virtual image.' The light isn't actually coming from inside the wall; it just looks that way because your eyes follow the straight path of the bounced light. Your brain perceives a 'twin' version of yourself standing exactly as far behind the mirror as you are in front of it.