Textures, antialiasing, and applying filters to make the rendered image look nice are all good, but I would argue that what really matters and everybody immedia

Textures, antialiasing, and applying filters to make the rendered image look nice are all good, but I would argue that what really matters and everybody immediately notices is the realistic modeling of ambient light. Proper global illumination is often what makes the difference between a sort-of-realistic looking scene from something that's hard to distinguish from a real image. The best known methods of doing global illumination are all based on tracing a lot of rays. Physically correct reflection and refractions are nice to have, but those aren't the only reasons to prefer ray tracing.