Place the diced potatoes in a large pot and cover with water. Boil the diced potatoes for about 20 minutes or until tender. Don't overcook the potatoes - they should be tender but not mushy.
Once the potatoes are fork tender, drain the water out of the pan.
Let the potatoes cool before mixing on the other ingredients. If you are in a hurry, you can rinse with a few changes of cold water to speed up the cooling process.
Put the cooled potatoes, onions, and celery in a large bowl. Add the mayo, mustard, pickles, sugar, salt, and pepper, and stir to combine. The amount of mayo will vary depending on the size of the potatoes. Add more or less if needed.
Sprinkle with a dash of paprika before serving if desired.
Notes
You can use any type of potato you like. I prefer to use Red potatoes or Yukon Gold potatoes. If you can't have mustard, just leave it out and add a little more pickle relish.Store leftovers in the refrigerator. They should be good for up to four days. Serving size is about ¾ cup.