The systematic error in patterns of responses to judgment and decision based problems in our life. Something which deviates from the usual responses.
The way you remember an event may be biased for a number of reasons and that, in turn, can lead to biased thinking and decision-making.
Everyone including your and around your, exhibits the cognitive bias. It is part of our daily thinking, decision making & choice based processes.
Cognitive biases may lead to more effective actions in a given context. Furthermore, allowing cognitive biases enables faster decisions which can be desirable when timeliness is more valuable than accuracy, as illustrated in heuristics.
Other cognitive biases are a "by-product" of human processing limitations, resulting from a lack of appropriate mental mechanisms (bounded rationality), impact of individual's constitution and biological state (see embodied cognition), or simply from a limited capacity for information processing. 
In previous issues, we have discussed about a lot of cognitive biases such as Optimism Bias, Self-serving Bias and Halo Effect.
These biases affect one’s decision making and choice making abilities.