Selfishness is good if you are focusing on yourself rather than on others.

Personality development, professional skill improvement in a way is selfish. You are trying to make yourself and your life better. By focusing on helping yourself first, you can become stronger and then help others in a better way .

If you trying not to become selfish by just focusing on other people and not on yourself then people may take advantage of you.

You may become the “nice guy/girl” who is always out there to help other people without thinking about yourself which in the long run can become harmful to you.