After read this:
Zhang's Ph.D. work was on the Jacobian conjecture. After graduation, Zhang had a hard time finding an academic position, partially due to a lack of support from his Ph.D. thesis advisor, Professor Tzuong-Tsieng Moh.[15] In a recent article, Professor Tzuong-Tsieng Moh recalled that "Sometimes I regretted not ?xing him a job" and "He never came back to me requesting recommendation letters."[14] He managed to find a position as a lecturer after many years, at the University of New Hampshire, where he was hired by Kenneth Appel back in 1999. Prior to getting back to academia, he worked for several years as an accountant and a delivery worker for a New York City restaurant. He also worked in a motel in Kentucky and in a Subway sandwich shop.[2] He served as a lecturer at UNH from 1999[16] until around January 2014, when UNH appointed him to a full professorship.[7]
This guy graduated from Purdue and his advisor didn't give him reference. He worked as an accountant and temporary delivery man in NYC Chinatown. This is a beautiful story that a genius eventually beats the odds.