Wow Factor
Wow factor is the memorable, emotive moment in a building, the point at which a space produces a genuine reaction rather than merely functioning correctly.
It is usually the result of deliberate contrast rather than expense. A compressed, low entry that opens into a double-height living space, a stair lit from above, or a corridor that ends in a framed view will all register far more strongly than a uniformly generous plan.
Restraint is what makes it work. If every space attempts to be the highlight, none of them is. Most homes can sustain one or two of these moments, supported by calmer spaces around them.
In practice the wow factor is often the cheapest part of a design, because it comes from geometry, light and sequence rather than from materials.