Bring a large pot of salted water to a boil. Add the macaroni and cook until just tender, about 8 minutes, stirring occasionally to prevent sticking.
Drain the cooked pasta in a colander and rinse with cold water until completely cooled and no longer steaming. Drain well and transfer to a large mixing bowl.
While the pasta cools, juice a lemon until you have about 2 tablespoons of fresh lemon juice. Set aside.
In a small bowl, whisk together mayonnaise, milk, and lemon juice until smooth and slightly runny, creating a creamy dressing.
Add the finely chopped celery, diced pickles, and shredded carrots to the pasta in the large bowl.
Pour the dressing over the pasta mixture and gently fold everything together with a spoon or spatula, ensuring all ingredients are evenly coated.
Season the salad with salt and pepper to taste. Mix again gently to distribute the seasoning.
Cover the bowl with plastic wrap and refrigerate for at least 1 hour to allow flavors to meld and the salad to chill thoroughly.
Just before serving, give the salad a gentle stir, taste for seasoning, and adjust if needed.
Serve the Hawaiian Macaroni Salad cold, garnished with extra chopped vegetables if desired, and enjoy its creamy, crunchy goodness.