Yesterday I shared the George Foreman Grill‘s remarkable journey from rejected “Fajita Express” to billion-dollar empire. But there’s something I maybe didn’t emphasize enough: the perseverance required. Remember those inflatable Bozo the Clown Punching Bags from childhood? The ones with sand in the bottom that pop back up no matter how hard you hit them? That’s what successful product makers often have to become. In Rocky Balboa‘s immortal words: “Life ain’t about how hard you can hit, it’s...