We have a lot of different words for feeling upset—like "angry," "frustrated," or "anxious." These are all words for when our brain and our body have too much stress. "Stress" is really just a mix of a few chemicals that make our brain and our body work a different way. Think of it like a potion. When you feel upset, it's like someone poured a cup of this stress potion onto your brain. It makes your heart beat faster. It makes your muscles ready to fight, freeze, or run away. It makes it harder to talk and harder to make good choices.