I'm applying to graduate school in physics, and I recently sent my personal statement to a professor for review. They sent it back to me today and told me that so-called "personal statements" are not actually supposed to be personal, linking me here as evidence. That article claims things like "Don’t give your personal reason for wanting to go to graduate school" and "Don’t make it too personal – this is a professional application." My professor said I should scratch references to, for example, how I got interested in physics initially in middle school, and so on. But I did some research myself, and found some articles such as this one that seem to imply it's a must to include how I initially got interested. In fact, the last paragraph of this article explicitly says "the most important thing is [to] keep it personal!" So, what is it? Are personal statements supposed to be personal or not?