Cats sleeping on people's necks feel safe. In fact, cats may feel uneasy or unsafe while sleeping, so they will look for a place where they feel safe. The human neck is one of the places where cats feel safe because it is close to the owner's face and breathing, giving them a feeling of protection.

Furthermore, the temperature of the human neck is relatively high, providing a warm sleeping environment for cats. Cats may choose this place to sleep because they are looking for a comfortable place to rest.