I began my educational career in Architecture. I loved thinking architecturally - designing - but was put off by the community of professional and aspiring architects around me. I encountered a tremendous sense of (self-)importance. Hubris. Ego.
You see, people build buildings with or without architects. What distinguishes vernacular building from Architecture is merely Architecture - in other words, its only noteworthy value proposition is itself. [I encourage you not to conflate the role of Architecture with the power of money or the advance of technology.] The argument for Architecture is circular.
If you compare the stakeholders of vernacular building respectively to the stakeholders of Architecture, you see a disproportionate emphasis on the architect him- or herself. Ego.
Product Design, a relatively new discipline, has piggybacked on the rationalization of Architecture, both for better and for worse. Product Design walks a dangerous line... the Product Designer, like the Architect, can get a big head. The Product Designer should be the humble servant, not the lofty bestow-er.
I think the Product Designer needs the consumer far more than the consumer needs the Product Designer. Our ego is almost always at odds with our ability to offer meaningful designs (which is to say, meaningful to the so-called "user").
On that last point, I think the most valuable lesson of post-Modernism is that the relationship is not designer-user, but designer-interpreter, designer-adapter, designer-arbiter. It is really through these - interpretation, adaptation, arbitration - and not through design that objects gain existential meaning.
I'm sorry if the tone of my response borders on self-loathing, but if one wants to make the argument that he is designing for someone other than himself, I think a little modesty is in order.