Milchmädchenrechnung

Milchmädchenrechnung: When you draw a naïve, oversimplified conclusion that ignores key factors, Germans will say you are making a “milkmaid’s calculation.”

Your bargain just got pricier. You drove 120 km for a half-price haircut, then fed your savings to the fuel pump and a roadside bratwurst. That, dear spreadsheet romantics, is a textbook Milchmädchenrechnung!