Cook the pasta according to package instructions and then drain well. Place hot pasta in a large bowl and sprinkle with the apple cider vinegar, stirring to coat. Let the pasta absorb the vinegar and cool for about 10 minutes.
Meanwhile whisk together 2 cups mayo, 1/2 cups milk, sugar, salt and pepper. Fold the macaroni salad into the dressing, stirring to coat and then let cool completely.
Add the remaining 1/2 cup milk and 1/2 cup of mayonnaise, along with any additional add-ins you would like, and stir to coat. Cover and refrigerate for at least 1 hour, or overnight. Stir before serving and adjust seasonings as needed. Enjoy!
This salad tastes best after it's had time to refrigerate and let the flavors enhance.