That thousand-yard stare when your frontend is pixel-perfect, your backend logic is flawless, but someone decided to store player names as "FIRSTNAME SECONDNAME" in the database.
Eight years of development experience and I'm still getting called at 2 AM because production data looks like a placeholder that escaped into the wild. Classic "works on my machine" until the real data hits and suddenly you're explaining to management why the soccer player's actual name isn't showing up during the European Qualifiers broadcast.