There is so much in the world that is not oneself, not under one’s control. Even one’s body, mind, house, and legacy often/ultimately are not under one’s control. Beyond seeking/providing the basics of a healthy life (livelihood, health/survival, family/friends, liberty/privacy/security, feelings of enjoyment or contentment, self-knowledge, etc.), what is the point of spending all one’s time building and maintaining big sandcastles, possibly at others’ expense? The less you have, the less you have to worry about (paraphrasing both the Buddha and my grandfather, who was not a Buddhist).