| 1 | Layout Stability | Click target moves; wrong thing clicked. |
| 2 | Feedback & Responsiveness | Action feels ignored; user retries, waits, or loses trust that the system is working. |
| 3 | Error Handling & Recovery | User is stuck with no way forward; input destroyed; problem unsolvable without guessing. |
| 4 | Forms & Input Interference | Platform fights the user's typing; data mangled, basic editing broken. |
| 5 | Focus | User is typing and the UI yanks them elsewhere. |
| 6 | Notifications, Interruptions & Dialogs | User's flow broken; attention taxed by noise; forced to parse ambiguous choices under pressure. |
| 7 | Navigation, Routing & State Persistence | User can't go back; context evaporates on refresh or redirect. |
| 8 | Scroll & Viewport | Content unreachable or unstable; user fights the interface to see what they came for. |
| 9 | Timing, Debounce & Race Conditions | Actions fire twice, responses arrive stale, sessions expire mid-task; system behaves unpredictably under normal use. |
| 10 | Accessibility as UX | Entire interaction modes broken — keyboard users can't navigate, touch users locked out. |
| 11 | Visual Layering & Rendering | UI elements overlap, clip, or hide each other; controls become unreachable. |
| 12 | Mobile & Viewport-Specific | Keyboard covers input, layout jumps on scroll, tap targets unresponsive; basic mobile interaction degraded. |
| 13 | Cumulative Decay & Long-Term UX | App degrades over time; preferences lost, performance rots, stale experiments create inconsistencies. |