🧭 Scenario · Make the call
The transfer that lost the money
The situation
A payment app moves $50 from Anya to Ben in two steps: first subtract $50 from Anya's balance, then add $50 to Ben's. One night the server crashed right after step one finished but before step two ran. When it came back up, $50 was gone from Anya but never arrived at Ben. The money simply vanished, and the books no longer balance.
You haven't read about this exact system. That's the point — walk the three questions a designer asks: what's really wrong, what fixes it, and what does the fix cost?
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Diagnose
Read past the story. What's the REAL problem — not what the feature does, but what's actually going wrong?
Look past the story. What's the REAL problem here?