Cook macaroni per package instructions until it is al dente, approximately 9 minutes. Do not overcook. Rinse in cold water at once. Set aside and let drain well but not dry out. Meanwhile coarsely chop celery and olives and finely slice green onions. (prepare any other solid ingreidentrs you wish to add.) Place in a large bowl and mix together. Add salt and pepper (plus other dry ingredients if used) to mayonnaise and mix thoroughly. Add up to an additional one half cup of mayonnaise if needed. Fold into macaroni mixture. Refrigerate two hours or, even better, over night to allow flavors to blend.