Just after college, I lived in a group house with a bunch of my college friends. At one point someone left and we had to interview strangers to find someone to fill the room.
We asked a bunch of the usual questions. What hours they kept, if they'd do dishes, did they smoke. Then we looked at them seriously and asked them this. "You're in a desert, walking along in the sand when you look down and see a tortoise. You reach down and you flip the tortoise over on its back. The tortoise lays on its back, its belly baking in the hot sun, beating its legs trying to turn itself over but it can't. Not without your help. But you're not helping..."
Anyone who looked confused and lost and said "what does this have to do with me living here?" did not get the room. Only folks who interrupted with "which desert" or "What do you mean I'm not helping?!?" were under serious consideration.