I am not sure it is always Cartesian in flavor, as the core of these ideas goes back farther into our religious history, but mind-body dualism and what Daniel Dennett calls the 'Cartesian Theater of the Mind' is a very hard thing to escape in our culture. Descartes did not really invent the aspects of his philosophy that are still with us everywhere, but he captured them clearly for all time. And we have a great deal of difficulty escaping them.
We rely heavily on the idea that there is an 'observer within' and that the body is just a device of the 'underlying soul' in many ways in common speech, in our religious thinking, and in other more subtle ways. For instance, our medical thinking about euthanasia is infected with the odd notion that a suffering human is unlike a suffering dog or other animal -- and that traces directly back to the doctrine of dualism and the separate soul.
Our attachment to the soul doctrine, and thus implicitly to Descartes' mediated dualism, makes it hard to imagine how the mind might have evolved, how the parts of our logic develop in babies and do not all come into being together in a single package, how perception and thought are integrated in situ and not serialized (neither comes first), how our language production processes are not mediated in the same way as our internal dialogue, etc., etc., etc.
We know these things are facts from physiological investigations -- reaction timing data in particular. But we find it very hard to elaborate models that allow for them because we cannot escape the biases captured and formalized by Descartes.
Dennett's "Consciousness, Explained" enumerates a lot of arguments against the "Cartesian Theater" and the whole book explicitly tries to give good alternatives for the Cartesian explanations that are tied too strongly to it.