Red walks into a store. Curious about a shiny object, she asks, "What is that?"
The store clerk responds, "It's a thermos."
Red then asks, "What does it do?"
The clerk says, "It keeps hot things hot and cold things cold."

So she buys one.

The next day, she brings it to work with her. Her boss asks, "What is that shiny object?"
She replies "It's a thermos."
He asks, "What does it do?"
She says, "It keeps hot things hot and cold things cold."
He then asks, "What do you have in there?"
"Two cups of coffee and a popsicle."