Define "a few"!
Prejudice, if not taken to extremes, is healthy. Prejudice, is just a bad name for the generalization of experience. You've met a few sharp knifes, so you learn to handle knifes with care. Even those you do not know. Even those that might be so blunt that you could not cut yourself no matter how much you tried. But what's "knifes are sharp" if not prejudice? Handling knifes with care is no worse neither better than making sure I have my wallet safe when a bunch of gipsy kids get on the tram/bus. Except that no one is gonna scream BS about racism when it comes to knifes. No one has made a nice living for him/her-self from "protecting" knifes.
You should be ready to change what/how you think about something/someone once you get more information about that individual, but banning "prejudice" is silly. And dangerous. Let's aim for moderation, not for absolute $whatever.
Enoch was right!
Enjoy the last years of Rome.