Used to love to go to Luby's and have the pasta salad. My mom had a friend that worked as one of the cooks there and she gave my mom the recipe. As far as I know, my mom didn't change it. Still tastes yummy.
quickly cool down pasta by placing colander into a bowl of ice water and stir to stop cooking process and drain well. (otherwise salad will be too runny)
in a big bowl, mix mayo and sugar and mix completely. If want to skip this step, use Miracle Whip. Add celery, onion and pasta (that is WELL drained). Stir together until mixed. May have to add more mayo. If using miracle whip, try to use mayo for the additional moisture otherwise it turns out too sweet.