The worst contaminant which affects our consciousness in the most negative way is being self-centered.
“Therefore it is his own self that is most dear to every embodied living being, and it is simply for the satisfaction of this self that the whole material creation of moving and nonmoving entities exists.” (Shrimad-Bhagavatam 10.14.54)
The souls come from the spiritual world to the material world due to developing a self-centered nature (I and mine). The material world with billions of universes is created for the purpose of providing the souls opportunities to be self-centered due to its own desires. The purpose of devotional service or bhakti is to develop a selfless nature and thus give-up the self-centered nature. This will free the soul from the material world and take it back to the spiritual world.
In the spiritual world, everyone lives in complete bliss, because nobody is self-centered. Everyone is a center for others happiness by having a service to all nature.
In the material world, there is chaos and suffering, because people are self-centered. Everyone is a target for looting, and using by the self-centered. There is no service to all nature, it’s all about “service to me” or “what’s in it for me”.