They always take things literally.
It taint yours and it taint mine :D (Puns for the win :D)
Because they take everything literally (p.s. you can steal this joke if you want)
A toothbrush.
Astronomy is about things too big to wrap your head around, while gastronomy is about things small enough to wrap your head around.
Boy explains his whole problem Girl: Oh, that's why you didn't notice my nail paint
Danke