Mix mayonnaise mustard and pickle relish until uniform in color and ure. Add vinegar sugar salt and celery seed and mix thoroughly. Pour sauce over potatoes and eggs; mix gently until potatoes and eggs are evenly coated. (I suggest adding the sauce half at a time so that you can add only enough to coat the potatoes and not have soupy salad!). Put potato salad into serving bowl and garnish as desired with sprinkled paprika (to taste) reserved slices of egg etc. Store in refrigerator for up to 2 days; serve cold. This recipe may be made vegan by omitting eggs and substituting vegan mayonnaise.