Tell me about a product you built where attention to detail made a significant difference.

Situation: I was building a mobile checkout flow for an e-commerce app. The feature was functionally complete and passed QA — all payment flows worked correctly, error handling was solid. Task: Before launch, I noticed several subtle UX issues during my own testing that weren't bugs but would affect the user experience. My task was to decide whether to ship on schedule or take time to polish these details. Action: I cataloged 8 specific polish items, ranked them by user impact, and proposed a 3-day extension to address the top 5. The details included: adding haptic feedback on the payment confirmation button, fixing a 200ms layout shift when the keyboard appeared on the card number field, matching the font weight in the total price to the visual hierarchy in the design spec (which was 100 weight off), adding a subtle animated checkmark on successful payment instead of just text, and ensuring the error state for declined cards matched the exact red tone used elsewhere in the app. Result: The 3-day investment paid off. Our checkout completion rate was 94%, compared to 78% for a similar flow at my previous company. User feedback specifically called out the payment experience as "smooth" and "polished." The PM later told me the attention to detail on checkout was cited in an investor meeting as evidence of product quality. The haptic feedback pattern I established was adopted as a standard across the app.