When the great Rabbi Zushya was dying, he lamented to his friends how little he had accomplished. Someone asked 'Rabbi are you afraid of the Judgment?' The Rabbi almost said 'Yes' but he paused, and then said, 'No. When I appear before the Almighty I will not be asked "Why were you not Moses?" I will only be asked, "Why were you not Zushya?"'.

See Parker Palmer's 'Let Your Life Speak'. http://jmm.aaa.net.au/articles/22628.htm