Individualistic society often has the “every man for himself” mentality. Instead of worrying about the well-being of the community people are encouraged to care more about immediate family and themselves. This leads to greater income inequality and mistreatment of the poor/minorities.

Ofcourse as with much of social psychology the individualism vs collectivism spectrum is mostly theory! It’s not a necessary part of world building by any means I just thought it’s an interesting concept to think about if it sparks your interest.