Obviously, judging entire groups of people based on when they were born is wildly ignorant. There are so many factors that affect how someone approaches the world (race/gender/sexuality/economics/religion/etc) more intensely than the year they were born, but it's also misguided to pretend generational differences aren't real.
One of the most glaring divisions between Millennials and Boomers is the genesis of a tech age that exposed many of us to computers from childhood on. This has affected everything from socializing patterns to the ways we think about shopping, and particularly the ways Millennials express discontent.
Growing up in an information rich age with wrecked economic prospects and constant advertising has massively shifted how Millennials approach our personal buying decisions.