After months of anticipation, second-guessing and exhilaration, Matt Kelly had a most surreal moment one day in late October.
It was during a break at Amazon.com Inc.'s Seattle headquarters, and the gravity of the situation sunk in for the chief executive of JBG Smith Properties (NYSE: JBGS). He and his team were there for three days of negotiations over the deal of a lifetime, bringing Amazon's coveted second headquarters to Northern Virginia. He couldn't let it pass without offering some advice…