►EXECUTIVE SUMMARY 1) ONE CUSTOMER WALKS — AND THE WHOLE P&L UNRAVELS: Buyer loses a single client worth 20% of revenue. Bad enough. But when he recalculates margins without that customer, he discovers most of his remaining accounts are way less profitable than diligence suggested. Some need to be fired immediately. 2) YOU'RE FLYING BLIND AND DON'T EVEN KNOW IT: The real gut punch wasn't the lost customer — it was realizing the entire accounting and KPI stack was inadequate. This buyer operated for months on garbage data. If your financial infrastructure is messy at close, budget 3-6 months and a dedicated hire to untangle it. You cannot afford to wait. 3) THE ONE QUESTION THAT EXPOSES EVERY WEAKNESS: "How does this business make money?" If you can't answer that with per-customer margins, per-project margins, and per-revenue-line margins — broken out by type — you don't understand the business you bought. Do as much of that analysis in diligence as humanly possible, because post-close surprises cost real money.