One thing I personally find rather disturbing is when one model comes along with a great, rather novel, look and even though people still love that look and the model still is in shape and great, another model comes around - sporting the same look - who becomes the favourite instead.
It just seems inhumane. Right now I'm thinking of Freja's replacement with Saskia, that seems to have taken place...I mean...as far as I know Freja is still around....