If the objects are reflected off an intermediate object, like a mirror, our perception of the original object may be distorted. The shape of the mirror also makes a difference in our perception. In the U.S., passenger-side mirrors are convex (curved slightly outward), whereas driver-side mirrors are flat.
Why is the passenger side mirror different?
The reason these two mirrors are shaped differently is because of purpose and function. The driver-side mirror needs to be accurate for traffic and distance reasons, while the passenger-side mirror needs to provide a wider visual field and to compensate for blind spots and its distance from the driver.