Understanding perspectives of graduate students throughout their developmental journey is at the core of preparing future faculty, and it can inform critical choices of graduate faculty members and program developers. This study investigated the most memorable and influential factors that both promote and thwart graduate students' success, across the graduate journey. We collected and analyzed participants' reflective, personal Most Significant Incident narratives. Online questionnaires were completed by 1,480 graduate students in a US research university. Two independent researchers thematically analyzed the data, for the whole-group and several subgroups. Findings demonstrated commonalities and notable differences between Masters and doctoral students, and between students at different points-in-progress toward degree completion. These findings illuminate processes and factors that can inform departmental and institutional policy and services for graduate students.