Why is Evan angry at his sister in the lemonade war?

In "The Lemonade War," Evan is angry at his sister, Jessie, because he feels overshadowed by her intelligence and success. He struggles with jealousy and frustration as Jessie challenges him in their lemonade-selling competition. Their sibling rivalry intensifies, leading to misunderstandings and heightened emotions, particularly as Evan grApples with feelings of inadequacy. Ultimately, his anger stems from a mix of competitive spirit and familial dynamics.