Fundamental attribution error
The inability to judge yourself and others to the same standard. Most people are happy to not judge themselves too harshly. So we’re more likely to assume that another person has done something wrong because they are a bad person rather than them being a victim of circumstance.
By concentrating on the subject's internal workings rather than also looking at the external factors, this bias means that we may make an assumption which is wrong and therefore everything that flows from that could also be wrong.