designed a system I'd never touched before in a system design round and just said the constraints out loud as I figured them out

Got asked to design something adjacent to a service I'd used but never built, and my brain went blank for a solid ten seconds. Started just narrating the tradeoffs I was unsure about instead of pretending I had a clean answer. Interviewer jumped in twice to nudge me, which felt like failing at the time but apparently that's just the round working as intended. Passed to the next stage anyway.