Zillow uses complex algorithms to estimate home values. The math is so tricky that Zillow once offered a $1 million prize to anyone who could fix their accuracy—a literal million-dollar admission that software has its limits.

The truth? Algorithms are great at counting rooms, but they’re blind to the details that actually sell a home. A computer doesn't know if:

• The house smells like cigarette smoke.

• The neighbor has three rusted cars on their lawn.

• The kitchen has $50,000 in custom marble.