Here are some key problems Greg faces:
* Social Isolation: Greg feels lonely and ostracized, especially after his best friend Rowley Jefferson starts hanging out with other kids.
* Lack of Confidence: He feels awkward and insecure, leading him to make poor choices, like trying to be friends with the "cool" kids who only use him.
* Dealing with Bullies: He faces bullies like the popular football player, Rodrick, and even his own older brother.
* Navigating Middle School: Greg struggles to adjust to the new environment, social dynamics, and academic pressures of middle school.
* Family Conflicts: He has disagreements with his parents, and his older brother constantly annoys him.
The story follows Greg's attempts to solve these problems, often through misguided and humorous methods, ultimately leading to personal growth and understanding.