From an economic perspective, giving the wrong gift makes society poorer. If you spend money on chocolates and give it to someone who happens to think it is worth less (due to an allergy!), you’ve lost value. Whenever you receive an outfit that is the wrong size or style, a candy you won’t eat, or something that is worth less to you than what the gift giver spent on it, an economic inefficiency has occurred. Thus, from an economic perspective, the most efficient gift is always cash. The person will maximize their own utility by spending (or saving) the money according to their preferences.
Submission and description from Erin Yetter!