bi·as
ˈbīəs/
noun
1. a particular tendency, trend, inclination, feeling, or opinion, especially one that is preconceived or unreasoned: illegal bias against older job applicants; the magazine’s bias toward art rather than photography;
http://www.dictionary.com/browse/bias?s=t
If you need evidence that bias is bad, there is a host of nonfiction literature by the likes of Nobel prize winning economists on the subject.