Dated a girl from work first year of college. On first "date", we decide to just make something simple at her place. Being rich college students, we settled with Mac and cheese and wine.
Get to the kitchen, and she says, "OK honest question. When boiling water, do you get the pot hot first, then add the water, or the other way around?"
Yup, she didn't know how to boil water. I just... don't know how someone makes it through life not knowing how to boil water on the stove.