Elaine and her old boss find that selling just the tops of muffins is more profitable than selling the whole muffin (which consists of the top + the stump). So are the top and the stump complements or substitutes? Neither--the stumps are an economic bad, which reduce utility. Evidence for this is found in the fact that homeless people won't eat the stumps that the muffin-top restaurant throws away, unless they come with the tops as compensation.
Jerry convinces Babu to serve Pakistani food—he'll be the only Pakistani restaurant in the neighborhood. Babu tells Jerry that the restaurant is failing and that Jerry is a very bad man. Babu's restaurant then closes. Jerry blames it on a bad location.
Jerry gets a bad haircut but refuses to change barbers because he is loyal. Eventually, he is convinced to leave his barber of 12 years for the barber's nephew. Bad quality doesn't persist in the marketplace; it is competed away. Perhaps the answer to bad haircuts is not more regulation, but more competition.