"Get a spaceship to Alpha Centauri next year. Oh, and it has to have a crew of at least 20 people, who all return safely to Earth by the end of the decade." I'l

"Get a spaceship to Alpha Centauri next year. Oh, and it has to have a crew of at least 20 people, who all return safely to Earth by the end of the decade." I'll leave you to think hard and find a creative way to make it feasible. Sure, sometimes you can re-define the goal. ("We need to know more about what's in the Alpha Centauri system.") But sometimes domain expertise means telling non-experts about reality. (Pi is not 3, no matter how much someone thinks it should be.)