Conscientiousness: Alice keeps putting off a project, since she knows it'll only take an hour (say, fixing a roof - after all, you only need to start an hour before the rainstorm). Bob just does it. Alice gets rained on.

Coonscientiousness: Alice and Bob's town is slowly invaded by a herd of raccoons. Alice looks up how to deal with raccoons, asks for advice, and looks for successful people and copies them. Bob just does what he thinks of first, yelling at them to stay away from his garden, until he gets to tired and raccoons eat all his vegetables.