When we have too much similarity, innovation dies. When we have too much dissimilarity, trust dies. We have to operate on a spectrum of chaos and stagnation.
What creates trust? Kunal found that trust is more natural in societies that have low diversity of ethnicity. We tend to trust people with common belief systems. Unfortunately, race plays a huge role.
It's not a surprise that most societies are not multi-ethnic because trust declines as it becomes more diverse in terms of ethnicity. We see the emergence of authoritarian leaders more frequent nowadays because low-trust societies always want somebody with a strong backbone to create peace.
One more nuance is if it becomes too similar, innovation dies. If it becomes too dissimilar, trust dies. Therefore, there's an interesting spectrum that we have to operate on between similarity and diversity. I'm unsure whether any scientific study backs Kunal's comments on ethnicity and authoritarianism, but it is a thought-provoking perspective to understand trust.