When I was applying to graduate school, the most common piece of advice was: “In undergraduate admission, they are looking for a reason to say yes. In graduate admission, they are looking for a reason to say no.” The reasoning was very practical. Universities and even small colleges have a dedicated department for undergraduate admissions with entire staffs whose full-time job is first recruiting then judging applicants. While many colleges have a central clearing house for graduate admissions, the main thrust of the admission work falls on the professors in the department themselves. Overall this is better, of course, because grad students will work much more directly and intensely with professors, who in theory want to choose their cohorts and likely TAs. But professors are asked to do this work on top of their full-time teaching, researching, and mentoring jobs. So YES, many of them are looking for mistakes in the submission or little oddities that allow them to t...