You should be afraid of yourself
because, it gives the impression that there is something wrong with you. But doesn't give you any indication of what that "something" might be. It sends your mind on a wild goose chase -- searching for a problem.
It's as though someone says, "there's something seriously wrong with you -- now go find it!" It destroys any feeling that you are OK. It makes you feel you should be somebody other than who you are. It makes you re-evaluate your whole life and question your existence in a negative way.
And, it is so destructive that it seems there is no way to resolve the endless search.
Unless you disregard the question. And accept yourself.
The worst teaching in the world is nothing more than a distortion of the best teaching in the world: Love God with all your heart soul and mind and love others as yourself. "There is no fear in love -- perfect love casts out fear."*
* 1 John 4:18. The "Great Commandment" is found in Matthew 22:37-39 and Mark 12:29-31, as well as Romans 13:9.