Language is the disk operating system of the brain. It allows for consistent retrieval of data by structuring the way each bit of information is stored. It allows more than one individual to share complex information. It allows them to learn from each other. Faith is a commendable asset, only when it is based on truth.
Bad faith is one based on a falsehood.
It is a set of beliefs that result in injury or limitation to the advancement of the species. Good faith is any set of beliefs that reinforce the species in it's quest for truth. I have seen my children mature from infants to young men and women. I have seen their tears, and their concern for people other than themselves. So I have faith and am comforted by it.