Hidden Bias

One of the things I'm eager to further understand, are the biases that people sometimes unknowingly expose, for instance a person behaves a particular way expecting to illicit a predicted outcome: A person pre-empting an emotional response, gossiping about a perceived belief in another, a pointed question that indicates a misalignment or miscommunication. I also think about how my own bias come out - assumptions about money being the first priority, or an assumption about someone's mood. I try very hard to listen and pay attention to these details. What are some biases or false assumptions you've experience and / or learned from?