When an individual or company designs for a target market, by definition this implies that there are people they are not designing for. Those who are left out/lie outside the designer’s interest are known as “edge cases.”
In reality, these “edge cases” are real-world people—an elderly single woman or a teenager with a physical limitation—whose needs can provide you with a goldmine of insights that could help your company be more inclusive and profitable by reaching more customers. But only if you’re willing to broaden your perspective.