What are some potential pitfalls of loading unnecessary data when using classes in PHP?

Loading unnecessary data when using classes in PHP can lead to increased memory usage, slower performance, and potential security risks if sensitive information is inadvertently exposed. To avoid these pitfalls, it is important to only load the data that is required for the specific task at hand within a class.

class User {
    private $userId;
    private $username;
    
    public function __construct($userId) {
        $this->userId = $userId;
        $this->loadUserData();
    }
    
    private function loadUserData() {
        // Load only necessary data from the database based on $userId
        // Avoid loading unnecessary information to improve performance
    }
}