Esprit de corps is when a group of people feel really good about being part of their team or group. Imagine you and your friends are on a soccer team. When you are all playing well together and everyone is cheering each other on, that's esprit de corps. It's like all of you are working together to achieve something important and it makes you feel happy and proud to be part of the team. When you have esprit de corps, you will work harder and do better because you want to help your team succeed. It's like being part of a big, happy family that works together and supports each other.