When you're building a global app, localization testing is the unglamorous but critical work. Most devs skip it until production breaks in a timezone 12 hours ahead. I used TestSprite on a real project last week and found exactly why that matters. The Setup I tested a payment dashboard against TestSprite's locale suite. The app handles USD transactions with dates, timezone-aware reporting, and currency formatting. Real project, real stakes. Here's what happened. Observation 1: Date Format Handling – The Silent Killer TestSprite flagged a critical bug in my locale handling that I'd completely missed. The Problem: My app was hardcoding MM/DD/YYYY for all users, even those in regions that use DD/MM/YYYY (UK, EU, Australia). Users weren't just seeing wrong dates—they were interpreting them incorrectly. A transaction marked 03/04/2026 looked like March 4th to a US user but April 3rd to a British user. In fintech, that's not a UX issue—it's a compliance nightmare.…