What are the potential pitfalls of not utilizing OOP in PHP programming?

Not utilizing OOP in PHP programming can lead to spaghetti code, making it difficult to maintain and scale the application. By using OOP principles, you can organize your code into reusable components, making it easier to understand and modify in the future.

// Example of utilizing OOP in PHP programming

class User {
    private $username;
    
    public function __construct($username) {
        $this->username = $username;
    }
    
    public function getUsername() {
        return $this->username;
    }
}

$user = new User('john_doe');
echo $user->getUsername(); // Output: john_doe