Failure mode is a term for a, usually common, way things fail when attempting something. for example, confirmation bias is a common failure mode in reasoning.
Knowing and understanding possible failure modes in what you attempting to do is important in order to avoid them.
See also: Postmortems & Retrospectives
Status Quo Bias
Heuristics & Biases
Mind Projection Fallacy
Pitfalls of Rationality
Guessing the Teacher’s Password
Expecting Short Inferential Distances