For the stovetop: Place drained corn in a small pan. Add water and cover. Heat over low until the corn is warm, about three minutes. Remove the lid and add the butter. Stir until the corn is coated. Season with salt and a pinch of sugar to taste.
For the microwave: Place drained corn in a microwave-safe dish. Add water and butter. Cover. Heat for 90 seconds or until the corn is warm. Remove the dish from the microwave. Stir to coat all the kernels with butter. Season with salt and sugar to taste.