For example, the pairing of PUT with 'update' , with only POST allowed to create new resource, versus allowing clients to PUT a new resource (effectively creating them) when given the proper URL.
See, for example, http://www.rgoarchitects.com/nblog/2009/06/23/CRUDIsBadForRE...
and in particular the idea that REST is about documents, not databases. "The data model is _not_ the resource model," as one comment there puts it.
Also, CRUD makes no allowance for HEAD and OPTIONS, as if they don't even exist.
I see too, in digging around for links, that this has been discussed on HN before (big surprise, no?):
http://news.ycombinator.com/item?id=629843