I read somewhere that the moment you pick an ear of corn, the sugars start turning into starches, or something like that. That’s why that ear right off the stalk is so sweet – it still has the sugar in it.
I take the freshest ears I can find (corn, not people’s), soak them for an hour or so in water, then put them on the fire or above the charcoal. Done in fifteen or so, depending on the heat. Butter, salt, pepper, cayenne (or a good chili powder).