What are the potential pitfalls of transitioning from procedural PHP to OOP, specifically in terms of user management and session handling?

Potential pitfalls of transitioning from procedural PHP to OOP in terms of user management and session handling include a steep learning curve for developers unfamiliar with OOP concepts, the need to refactor existing code to fit within an OOP structure, and the risk of introducing bugs during the transition process.

class User {
    private $username;
    private $email;

    public function __construct($username, $email) {
        $this->username = $username;
        $this->email = $email;
    }

    public function getUsername() {
        return $this->username;
    }

    public function getEmail() {
        return $this->email;
    }
}

// Example usage
$user = new User('john_doe', 'john.doe@example.com');
echo $user->getUsername(); // Output: john_doe
echo $user->getEmail(); // Output: john.doe@example.com