Richard Pryor
Richard Pryor made his career as a comedian, but he was discharged from the military when one joke went awry. While watching the film Imitation of Life, there was a racial joke that made one army man fall over with laughter. Richard Pryor and other soldiers attacked and stabbed the man for laughing so hard at the racism, but the beating was not fatal. He went to NYC to do stand-up following this incident.
JRR Tolkien
After getting married to his wife, Edith, World War I began. Tolkien opted to delay his enlistment to finish his degree, which angered his and Edith's families. He once wrote to his son, "In those days chaps joined up, or were scorned publicly. It was a nasty cleft to be in for a young man with too much imagination and little physical courage." Tolkien has publicly spoken about his distaste for being there.