“Come on, little fella – we should get going now.” But my son was not listening. The sand in the playground was just right, so he kept digging with his new toy excavator. As I drifted back to my list of to-dos, however, the laughter was suddenly replaced by sobs. My son was not hurt, just very upset. When I looked at my phone, I saw it was well past his regular mealtime – and he was feeling very hungry. However old we are, we all have a tendency to grow irritated if our body lacks enough fuel.