Why was jess angry at Leslie in Bridge to Terabithia?

Jess was angry at Leslie in "Bridge to Terabithia" because he felt betrayed when she invited other friends to their secret place, Terabithia, without him. He was also struggling with his own insecurities and the fear of losing their special bond. This anger was compounded by his feelings of isolation and frustration in his life, making him lash out at Leslie. Their friendship faced challenges, highlighting the complexities of young relationships.