Add the crab meat to a large bowl, then top with the mayonnaise, sour cream, salt, and pepper, lemon juice, dried dill, and red pepper flakes if using.
1/3 cup mayonnaise, 1/3 cup sour cream, 1/2 teaspoon lemon juice, 1/4 teaspoon dried dill, salt and pepper to taste, 1/4 teaspoon red pepper flakes