Racism

I can't be the only one who finds the idea of it completely irrational. I don't really get the concept of it. Its basically based on the stereotypes of a group or a single person of that race doing something you find wrong, which shouldn't represent the entirety of the race. I've met good people of practically any race, and I don't really understand why people could hate all people of a certain skin tone. General's thoughts on it?