Panera and Postmodernism

Today i was driving to work (read: place i go that pays me to do something i love), and i was behind a truck belonging to a very well known bread and restaurant company. On the back of the truck was a picture of a very appealing looking loaf of bread, ostensibly right out of the oven, with the caption under it reading: "Unsliced Bread...the Best Thing Since Sliced Bread". i stopped and stared at it (well...i didn't have a choice...there was a red light...and i am a law abiding citizen), and i felt a slight sense of intrigue and maybe a bit of condescension...
Don't get me wrong, i love the occasional ironic turn of phrase. no one appreciates plays on the English idiom more than I. especially when they might prey upon standardized, socially acceptable norms. maybe I'm just a rebel at heart clothed in this disguise of a rule lover...whatever the reason, i do love all the nuances involved in turning a phrase on its head to do anything from getting a laugh to making a point...philosophical, sociological, metaphysical, theological, or otherwise.
But...this one got me thinking and musing. So much so that i whipped out my trusty iPhone and quickly snapped out a snarky little response in my "notes" section. (At the stop light)
I looked back on it today and from what i could discern through the hastily typed and oddly autocorrected words (darn you, iPhone!) was that, then, and now, i am fascinated by how much, to borrow the colloquialism, "The more things change the more they stay the same".
No, i am not finally bowing to a cliche to express myself. fear not, i fully intend to broaden the scope of my feelings here. but that is basically what i pounded out on my keypad to express my incredulous feelings. well...honestly not really "incredulous"...much of this culture's fascination with postmodernity and its subsequent infiltration in marketing has lost all surprise for me.
I guess what really struck me was how much we crave to be different. once something becomes the norm we must move on to the next thing lest we become "normal" (gasp!) and therefore, we are told, irrelevant. Remember when Northface was all the rage? phsst, that was SO Jr. High. It's why Mac's, which used to be the norm, then were old news and outdated, are once again so popular in the face of an industry saturated with all things Microsoft. (I admit, it may be trendy and thus regrettable later...but I LOVE all things Mac.)
Why does that statement on the back of a Panera truck strike so many chords? why does it really, honestly, hit home and actually convince people to buy bread there? is it the draw of a bakery that provides a bread buying experience that we associate with some nostalgic time in the past (that neither we, nor our parents, actually had any part of!) so it thus must be profoundly more appealing?
Or is it just the fact that since Panera says it, and it sounds funny and maybe slightly profound...in a rather cheeky way...we feel that its the way we ought to feel? Maybe...but i honestly think its more than that. its really the human heart and spirit to want new. to want better. to want the different. to crave change. In today's space and time we tend to revert back to history, to the old, to the times of yore; craving this eclectic collage of past and present that, broadly, constitutes the core of postmodern culture. And i would never argue that this is always bad. i just wonder WHY. And perhaps more importantly, i wonder how our lives would be different if these urges, embedded deep in our psyche and culture, did not drive our rabid consumerism.