In a small bowl, combine brown sugar, smoked paprika, garlic powder, onion powder, chili powder, salt, and black pepper to create the spice rub.
Pat the pork shoulder dry with paper towels and rub the spice mixture all over the meat, pressing gently to help it adhere.
Place the seasoned pork shoulder in your crockpot. Pour apple cider vinegar and Worcestershire sauce around (not over) the meat.
Cover and cook on LOW for 8 hours or HIGH for 4-5 hours, until the meat shreds easily with a fork.
Remove the pork from the crockpot and let it rest for 10 minutes. Reserve the cooking liquid.
Shred the pork using two forks, discarding any large pieces of fat. Mix in 1/2 cup of the reserved cooking liquid for moisture, adding more as needed.
Taste and adjust seasoning with salt, pepper, or additional vinegar as desired. Serve immediately.
Notes
Storage tip: Keeps in fridge for up to 5 days. Store with some cooking liquid to maintain moisture. Freezes for up to 3 months. Reheat gently with a splash of liquid to prevent drying out.