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

[Belacqua]

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.”