Have you ever been really hurt by a conclusion regarding your behavior that is absolutely false? You may have failed in one regard, or even in a couple, but it doesn't justify a blanket condemnation. You forgot someone's kind invitation and then you are told you are generally callous and lazy, and deserve to lose friends?
What this shows is that the person is hurt that you forgot them and angry. Such a conclusion (that you are callous and lazy, and deserve to lose friends) is a hasty generalization (a conclusion drawn from insufficient statistical evidence). It is a formal logical error/ fallacy.
"This fallacy is committed when a person draws a conclusion about a population based on a sample that is not large enough. ...
People also commonly commit Hasty Generalizations because of laziness or sloppiness. It is very easy to simply leap to a conclusion and much harder to gather an adequate sample and draw a justified conclusion. Thus, avoiding this fallacy requires minimizing the influence of bias and taking care to select a sample that is large enough. ...
Smith, who is from England, decides to attend graduate school at Ohio State University. He has never been to the US before. The day after he arrives, he is walking back from an orientation session and sees two white (albino) squirrels chasing each other around a tree. In his next letter home, he tells his family that American squirrels are white."
I'm fallible and I am not omniscient, but I'm definitely not callous or lazy. I hate to lose friends, ever for any reason. Perhaps for Boethius there was Consolation in Philosophy. For Phil there is Understanding in Philosophy, but often no Consolation. :(