Apples.

Mary has an apple. Jane also has an apple. I don't like apples, so I don't have one.

Mary's apple is red. Jane's apple is green. I don't have an apple, so I don't have any colors.

Mary and Jane are always insisting that their apple is the real fruit when they themselves haven't never taken a single bite. I don't have an apple, so I don't say anything.

Mary and Jane, seeing that I have no apples, tell me that I will definitely die soon because I don't eat apples.

Mary and Jane meet another friend who has a pear. They tell her that she will also die soon because a pear is not the real fruit.

I ask Mary and Jane why they thought that people who don't have apples will die soon.

They say they read it from a recipe.

I ask Mary and Jane who wrote the recipe.

They say a great chef wrote it.

I nod, and left them to continue their argument.