I want to begin with Coca-cola. It’s no surprise that Coca-cola was first introduced as a medicine. Its strange taste seems to provide no particular satisfaction. It is not directly pleasing, however, it is as such, as transcending any use–value, like water, beer or wine, which definitely do quench our thirst, that Coke functions as the direct embodiment of "IT", the pure surplus of enjoyment over standard satisfactions. It is the mysterious and elusive X we are all after in our compulsive consumption. The unexpected result of this is not that, since Coke doesn’t satisfy any concrete need we drink it only as supplement, after some other drink has satisfied our substantial need — it is rather this very superfluous character that makes our thirst for Coke all the more insatiable. Coke has the paradoxical quality that the more you drink it, the more you get thirsty. So, when the slogan for Coke was "Coke is it!", we should see in it some ambiguity — it’s "it" precisely insofar as it’s never IT, precisely insofar as every consumption opens up the desire for more. The paradox is thus that Coke is not an ordinary commodity, but a commodity whose very peculiar use–value itself is already a direct embodiment of the auratic, ineffable surplus. This process is brought to its conclusion in the case of caffeine–free diet Coke. We drink a drink for two reasons: for its nutritional value and for its taste. In the case of caffeine–free diet Coke, its nutritional value is suspended and the caffeine as the key ingredient of its taste is also taken away. All that remains is pure semblance, an artificial promise of a substance which never materialized. Is it not that in the case of caffeine–free diet Coke that we almost literally drink nothing in the guise of something? What I am referring to, of course, is Nietzsche’s opposition between "wanting nothing", in the sense of "I do not want anything", and the nihilistic stance of actively wanting the Nothingness itself. Following Nietzsche, Lacan emphasized how, in anorexia, the subject doesn’t simply not eat anything, he rather actively wants to eat the Nothingness itself. The same goes for the famous patient who felt guilty of stealing, although he didn’t effectively steal anything — what he did steal was, again, Nothingness itself.- Salvoj Zizek, "The Supergo and the Act"