I'd like to know exactly when to remove popcorn from the microwave. If I leave it in a little longer, a few more kernels will pop, but I might burn the popcorn. if I take it out too early I may leave some unpopped kernels. Usually one listens for when popping stops, or when the last pop happened, but some bags of popcorn finish much faster, so that means there's more time until burnt.
Take it out once the pops are more than one second apart. Although this will leave some unpopped kernels, it will prevent the popped kernels from burning.