Introduced by George L. Kelling and James Q. Wilson, the Broken Windows Theory describes how fixing the smallest signs of disorder prevents larger problems from taking hold. A single broken window that stays unfixed signals apathy and invites more damage. Fix the window quickly, and the environment signals the opposite. When David Gunn took over the New York City Transit Authority in the 1980s, the subway was filled with graffiti, broken lights, unreliable trains, and constant vandalism. Gunn applied Broken Windows thinking to the entire system.

He focused on the little signals that shaped how riders felt about the system:

• Clean every subway car completely.
• Remove graffiti immediately so it never stays long enough to become normal.
• Repair broken doors, lights, and signage before moving to large infrastructure work.

These were symbolic and practical signals. When graffiti disappeared, vandals lost motivation. When doors worked reliably, people entered the trains more calmly. When the environment improved, the behavior changed around it.

Gunn’s work mirrors modern UX principles: small interface signals shape user trust more than big strategic announcements. A broken button, a slow loading bar, or an inconsistent layout creates the same effect as a broken window in a neighborhood. It tells users that the system is neglected, so they lower their expectation and often abandon the flow.

Fixing tiny usability issues has the opposite effect. Clean transitions, predictable navigation, accessible states, and fast responses create trust and reliability. Over time, those cues change user behavior and confidence in the product.

Gunn’s subway cleanup reframed UX for me. It is less about feature delivery and more about continuous maintenance of an environment. Trust is built through many small repairs, not occasional big redesigns.