To provide a counterpoint to what people are saying, don't assume that you have nothing to contribute to part D. what may seem rather mundane and boring to you might be absolutely fascinating to someone else. At the same time, if you feel that your personal statement, supplemental and PharmCAS will be enough to tell the story, then by all means leave it at that.
Also, don't be intimidated because it's UCSF and of its reputation. There are people who got into UCSF who have had the 4.0 GPA, stellar LORs, perfect extracurricular activities...and you've got people like me with the 2.6 GPA and barely got his bachelor's degree, but turned his life around enough to get in 15 years after he screwed up the first time.
And there are people with the 4.0 GPA, stellar LORs, etc., etc., who get rejected or waitlisted.
The UCSF supplemental is left intentionally vague and not clearcut so that it forces you to think about how you'd answer the question. It's to your advantage to be creative in your responses so that the real you comes out in your supplemental.
The one common theme that I've heard all throughout everyone who's gotten accepted for this class is shock that we all got in because we all felt that we didn't fit the supposed perfect student that comes in with getting into UCSF. To that end, everyone I've met is surprisingly and incredibly humble, but then when we all talk, we've all got amazing stories to tell about who they are as people and how they got in. The SF people have met about 3-4 times already, and everyone I've met is genuinely nice and sincere. And still shocked--even though school starts in a month!
I think the biggest piece of advice I can give you is--be yourself and don't pad your resume and supplemental with BS. It'll come through in your application, and most definitely in your interview if you somehow make it that far.
Good luck and feel free to PM me if you have any questions.