As I think back on the great advice I’ve received over the years, I’m surprised to realize that some of the best advice came from very random sources — books I skimmed, people I hardly knew. Like my former law-school roommate’s ex-boyfriend’s advice. It has guided me for years — and I never even met the guy! And yet I’ve thought about his advice so many times: “Successful people are willing to do things that unsuccessful people are not willing to do.” What do you think of that advice—do you agree? And have you ever picked up important advice from an unlikely source?