"Are all actions in life based on interest only"?

[Anomalocaris]

In evolutionary biology there are four common types of social behavior that get studied: Altruism, selfishness, mutual benefit, and spite.

Spite occurs when an animal harms itself in order to harm others.

Have you heard the joke that Zizek tells about this?

Once there was a Slovenian farmer who worked on his farm. One day, a god-like figure approached the farmer and offered him a deal. The god-like figure says “I will do whatever you request to you, but whatever I do to you, I will do twice that to your neighbor.” The farmer thinks for a moment then replies, “Take one of my eyes.”

If his neighbor doesn’t have children, then he would do better to tell the god like being to take one of his testicles.