If someone looks, talks, smells and has the same DNA as I do - exactly like me except they are obnoxious - I will not like them because they are obnoxious.
Unless I am obnoxious, too.
There's always going to be something.
Glitch, you are right that we tend to stereotype based on our personal experiences and based on superficial criteria. (ETA there are evolutionary reasons for this. Our primitive ancestor needed to quickly associate a new creature bearing saber-tooth fangs with the cat that ate baby brother yesterday; to do otherwise was fatal.)
But educated people (certainly including you) recognize that the result isn't reality.