“Happiness belongs to those who are sufficient unto themselves. For all external sources of happiness are, by their very nature, highly uncertain, precarious, ephemeral, and subject to change.” – Arthur Schopenhauer
There is nothing wrong with self-interest as such. We need to take care of our biological selves, make sure we have adequate food, water and shelter, avoid danger, take rest and ensure our other basic needs are met. Without this basic level of self-interest none of us would survive for very long.
Today, however, we in the more developed countries need to spend very little time and energy fulfilling these physical needs. If we are hungry or thirsty we simply go to the refrigerator, or we can get in our car and drive down to the supermarket – in the middle of night in many cities.