Have you ever gotten really, really angry because you lost a game, because your sibling took a toy, or because dad said "no"? It's normal to feel angry!
The problem is what we do with it. The "volcano kid" (whom the Bible calls a fool) starts yelling, throwing things on the floor, and saying mean words. The volcano's lava burns the whole house's happiness!
But God gave you the Fruit of the Holy Spirit, which has a superpower called "Self-Control." The kid who uses that power closes their little mouth, takes a deep breath, and holds the anger inside without exploding. When you can calm down without yelling, your Father in Heaven applauds from up there, because you're acting just like Jesus!