Right. To put a finer point on it, the insidious part is that advertising teaches us not what to want, but how to want. It doesn't say "a Mercedes makes you worth something", it says "only the things you buy can [make you valuable|entertain you|satisfy you|make life worth living]", which ingrains certain behaviors.

It's like the Dark Side version of the "...teach them to long for the endless immensity of the sea" quote.

Edit: and it really goes even deeper than that, teaching us that being constantly entertained or totally satisfied is the state of being everyone else is in (so why aren't you?) --> only buying things can get you there --> here, buy this.