Preppies live very privileged lives (and we all know it too) and they are grateful for the opportunities given to them. They realize that not everyone lives a charmed life and are therefore not brats such as those on MTV's Super Sweet 16, but rather they acknowledge how much mom and dad have done to give them a good life, and are properly grateful.
Another defining characteristic of preppies is their work ethic. Preppies work hard for top grades and to be admitted to top-tier prep schools and colleges. The myth about daddy paying for lazy kids to go to Yale is not true. Our parents feel we should work to get to the top, and our work ethic usually pays off, which is why you find us at colleges such as Dartmouth and Yale.
There is, of course, the matter of the distinct preppy clothing style. Rather than the mall shops such as Hollister and American Eagle where the so-called "mainstream preps" shop, a real New England preppy shops at stores such as Vineyard Vines, J.Crew, Ralph Lauren, Lacoste, and Murray's. These clothes are admittedly more expensive than those found in the mall, but they are of much better quality, and therefore last longer, proving to be a smarter, better investment. The reason we can get away with wearing clothing for so long is because preppies do not follow trends. Our style of polos (collars popped essentially until marriage), khakis, topsiders, and other classic pieces has been in style for decades, and will continue to be in style for decades to come.
A preppy has been given opportunities but rather than waste them or take them for granted he or she works to earn this privilege after the fact. Class act.