There is a reason behind everyone you meet

I hear a lot of Christians say, "There is a reason behind everyone you meet."  It's part of that feel good mysticism they like to promote but there is no substance behind it.  By reason they are presuming a purpose or destiny.  Think about it for just a moment.  Everyone you meet.  What if you met Jeffrey Dahmer?  What could be the destiny behind that?  That you survived?  I met Bozo the clown and about a year later I was traumatized by a Shriner dressed like a clown.  Now I am afraid of clowns.  What was the purpose behind my meeting Bozo if I now fear clowns.