Humans and animals have different concepts of comfort. While humans prefer a pleasant environment free from intrusive odors, animals feel comfortable in surroundings marked by their own scent. This leads to a conflict between humans and animals. To make their homes cozy, people clean and ventilate their living spaces, which can be unpleasant for their pets. Conversely, pets create problems for their human housemates through their efforts to make the environment comfortable for themselves.