Family restaurant: The waiter often asks, "Kids' menu or adult menu?" If you're an adult who simply wants a smaller portion, it's easier to say "kids' menu" rather than explain that you don't have children but would prefer a smaller plate. The implicit framework is designed for families, not for adults with smaller appetites.
Sports store: The salesperson asks, "Is this for men or women?" to direct you to the gendered sections. If you're looking for running shoes based on your foot shape, it's quicker to answer according to the suggested category than to explain that you prioritize performance over gender.
Pharmacy: When buying vitamins, the pharmacist often asks, "Is this for children or adults?" If you want a supplement for a specific purpose (intense sports, pregnancy, recovery), it's easier to conform to the suggested dichotomy than to detail your personal situation.
These examples show that the consumer conforms to social shortcuts to facilitate the exchange, even if their real need does not exactly correspond to the implicit categories of the seller.