Cook the elbow macaroni according to package instructions until al dente. Then drain and rinse under cold water to cool. Set aside to drain completely.
In a large bowl, mix together mayonnaise, white vinegar, Dijon mustard, sugar, salt, and pepper until smooth and creamy.
Add the cooled macaroni to the dressing and toss to coat evenly.
Fold in the celery, red bell pepper, and red onion, ensuring the veggies are well distributed throughout the pasta.
If you're using hard-boiled eggs, gently fold them in too at this point.
Cover the bowl and chill in the refrigerator for at least an hour to let the flavors meld together. The longer it sits, the better it gets!
