Yes, we all use our personal filter for one reason or the other because that's just how it works. We're not infallible omniscient beings so we CANNOT help it, But, if we understand this and consciously think about this everytime we speak or intergect into a conversation we can at least limit bias.
True, it matters what motivates your ability to reason. Most people rationalize in the vanity of their own minds instead of the reality of life. Without absolute truth to guide us, there is no sound reason.