Cook macaroni, according to package directions, until al dente. Drain and rinse the pasta under cold water so that it stops cooking. Set aside.
Mince the celery, carrots, red onion, and parsley, then toss stir into the drained and cooled macaroni. Stir in the chopped, boiled eggs.
In a separate bowl combine the mayonnaise, milk, lemon juice, lemon zest, salt, pepper, paprika, and cayenne pepper. Fold into the macaroni mixture.
Taste, and adjust seasonings as needed. Store covered, in the refrigerator. It tastes best after it has sat in the refrigerator for a bit, to let the flavors blend together.