`Without a unified language, all products drift toward inconsistency.` - Teams don’t *choose* to be inconsistent. The drift goes hand in hand with scale. - The larger issue is what this inconsistency represents (and exacerbates): a lack of alignment and communication across teams, a diluted brand voice, and a disjointed user experience. - Design systems create better products when they provide both unity and cohesion. *Unity* means that things feel complete—all of your brand elements work together as one. *Cohesion* is the quality that makes your ~~user interfaces~~ brand easy to understand across the experience. - Unity is easier to accomplish than cohesion, because it can be solved by creating tools: style guides, brand languages, shared components. Cohesion is more complicated because it can’t be solved with a tool alone. In order to create products that feel cohesive, you need to align teams around a shared definition of how your brand should look, feel, and behave. - Designing products requires making hundreds of decisions quickly. ==A small team can rely on tribal knowledge to ensure that those decisions are consistent.== But as teams grow, the ability to make aligned, consistent decisions becomes harder. Your products won’t feel cohesive if everyone is working from a different definition of “quality.”