human nature; the way people are
A set phrase meaning 'it is human nature' or 'that's just how people are'. Often used to express resignation or understanding about universal human behavior.
It is human nature to make mistakes.
Being drawn to beautiful things is just human nature.
A classical Chinese-derived phrase composed of 人 (person) + の (possessive) + 常 (usual, constant), literally 'the constant of people'. It has been used in Japanese as a set expression for centuries.