There are many unknown elements in an unhealthy home that do not set us up for success. There often times is ongoing danger, multiple times a day, which sets us up for feeling we are always at risk. There is a constant unknown.
There is inconsistency. To the brain, that is an unknown. Will Dad come home from work happy or angry? How about mom, what will her mood be like? We are constantly on guard because we don’t know what to expect due to a lack of consistency.