Reply To: Taking isolated negative experiences we had and generalizing across all people

If one does it it is called “prejudice.”
Of course one should not judge a group of people based on negative experiences with someone in that group.
However, one may use caution in dealing with them.
Remember the story from the Gemara that the rabbi let a unknown person stay overnight at his house but he took away the ladder. (so he could not get down and possibly rob them.)