Form follows function.
This has inspired generations of "modern" architects and justified designs seemingly stripped of ornamentation and excess. To satisfy market demands, most building product manufacturers have had to offer materials similarly devoid of ornamentation, allowing the function of the product to speak for itself.
But architecture can also borrow insight from other creative fields. Willie G. Davidson, Chief Styling Officer for Harley-Davidson -- a very successful brand -- proffers a small but significant twist on Sullivan. Davidson says:
Form follows function, but both report to emotion.
I see this expressed in the current issue of McGraw Hill's SNAP magazine - a publication that survives by appealing to architects. It's cover photo depicts a pair of trash receptacles, a product category not ordinarily considered exciting.
But without sacrificing functionality, the manufacturer of these trash cans added an entasis (architecture for "curvature"). showed sensitivity to color and texture, and created an object with emotional appeal to designers.
Svelte objects of sensual desire may not elicit the right emotion for your company -- many building products, for example need to appeal to emotions of safety and reliability, for example -- but you cannot afford to overlook emotion in your branding.