I definitely undervalued volunteering for admissions purposes. Fortunately I was still involved in volunteer work due to personal interest, but I thought research would be a way more important part of my app -- it turns out that volunteering ended up being the highlight of my application, while my research was almost a side note. I also thought that if my GPA dipped below a 3.7, my chance at admission to
any medical school was basically zero and that I'd have to give up and find a new career. I even threw away my copy of Gray's Anatomy (the book) after one poor GPA semester, because I couldn't bear to look at it since I "knew" I'd never get into medical school. For awhile I was also convinced that applicants needed to be super talented at some unique, high-level, non-medical hobby (world-class musician, NCAA sport) in order to attract the attention of a top school.
I have no idea what I was thinking back then.....