An airhead walks into a store and is immediately curious about a shiny
object on sale. He asks the shop assistant, “What is that?”

The assistant responds, “It’s a thermos.”

“What does it do?”

“It keeps hot things hot and cold things cold.” So the airhead buys one. 

The next day he brings the thermos to work with him. His boss, also an
airhead, asks, “What’s the shiny object?”

“It’s a thermos.”

“What does it do?” 

“It keeps hot things hot and cold things cold.”

His boss then asks, “What do you have in there?”

The airhead replies, “Two cups of coffee and a popsicle.”

One Liner
My grandfather has the heart of a lion and a lifetime ban from the local
zoo.