As an illustration, consider two women who are lawyers, from the same nation, who are roughly the same age and look alike. One establishes and grows her own company. The other build businesses for other people. Both of them are mothers. It is simultaneously very similar and very distinct. However, one became wealthy, took the money, and left, whereas the other took a salary job, stayed, and assisted others. I began to ponder what it is that differentiates them and motivates their behavior. The answer is very simple: Greed.
The Bible does not forbid acting in one's own best interests. In Philippians 2:4, Paul makes this extremely plain, saying,
"Let each of you look not only to his own interests but also to the interests of others."
When you prioritize your interests over those of others, a problem develops. Greed clouds people's capacity to think realistically. It devours humanity. The conscience is being skimmed. An uncontrollable drive for more material wealth can cause people to even forget about their friends and family.
Speaking of which, I believe that understanding self-interest in the context of our life and work is essential. Our aim should be to strike a balance between our needs and those of others. Only then our self-interest will avoid turning into greed.