Caviar

Bob: "You know, sometimes when I'm eating caviar, I feel kinda guilty."

Bobb: "Why's that?"

Bob: "Because there are starving people all around the world, and if I'm gonna spend hundreds of dollars per ounce on a bunch of fish eggs, then I can obviously afford cheaper foods. You know? Then it wouldn't seem like such a waste."

Bobb: "Well, yeah, but how many poor people can afford caviar?"

Bob: "That's exactly my point."

Bobb: "No, you're not following. Poor people can't afford expensive foods, and yet there will always be expensive foods out there. Poor people will never eat caviar, because once they can afford it, they're obviously not poor. You're not taking food out of their mouths because you're not overlapping with any foods they'll actually eat."

Bob: "You're a horrible person."

Bobb: "In fact, you should only feel guilty when you're eating cheap, easily accessible foods. You're driving up demand, and therefore, price, which makes it harder for the poor people to afford it. Shame on you. Next time you get a craving for macaroni and cheese, bite your tongue and buy a steak."

Bob: "How do you sleep at night?"

Bobb: "Ever mix antihistamines with alcohol?"