Why do Lauren Conrad and Kriten Cavellari hate each other?

Well Lauren had this best friend name Stephen Coletti. She had a crush on him, but he was going out with Kristen. Kristen was angry that Lauren and Stephen were hanging out too much so she told him to stop. Lauren and her had an argument and have disliked each other ever since. Another reason may be because they both went out with Brody Jenner as well.