Realized halfway through a system design interview I was designing for a scale nobody asked for

Was mid-way through designing a URL shortener for '10 million requests per second' before the interviewer gently asked where that number came from. I'd just defaulted to FAANG-scale assumptions because that's what every system design guide opens with. Realized afterward I'd never once asked about the actual expected load in the problem statement. Small habit, but apparently an expensive one to skip.