When melakhot are permitted on Yom Tov for food preparation or other Yom Tov pleasures, they are permitted on condition that one performs them for the sake of something which is shaveh le-khol nefesh, which means that most people derive benefit from it. In contrast, one may not perform melakhot for the sake of something from which only those who are overindulged or ill normally derive benefit. The Torah states: “Only what every person is to eat, that alone may be prepared for you” (Shemot 12:16). This does not necessarily mean that everyone must enjoy it regularly, but that most people, if given the opportunity, would enjoy it. Thus, even though few people have ever trapped a deer and eaten its meat, since most people would be happy to eat the meat, slaughtering it on Yom Tov is considered shaveh le-khol nefesh. Similarly, food may be seasoned with expensive spices that most people cannot afford, because most people would be happy to use them in their food.
In contrast, one may not place incense on coals in order to perfume the room or clothes that one places above the coals, because most people, even if offered the opportunity, would not perfume their homes or clothes in this way. Therefore, one who does so violates the Torah prohibitions of Mav’ir and Mekhabeh (Beitza 22b; Ketubot 7a; 5:10 below).