No matter what people say, a good set of essays can take you almost anywhere. Take note that I made essays plural, rather than singular. Most people emphasize the importance of the common app. essay, but the personal statements are just as, if not more, significant in the process. This is something you'll find to be true not only through admission decisions, but also as you write your applications. If you can write a very eloquent essay filled with lots of reasons for the "why us?" question, then your reasons for wanting to go should carry you through. However, if you're struggling for an answer and you try to B.S. your essay, the admissions officers will be able to tell. You're guarantied a rejection if you B.S. your essay, and admission is a pretty safe bet if you can argue your case effectively.