Today I went to see my uncle. He is a flying squirrel. He always explores the forest and usually finds a lot of interesting things. I found him on a branch holding a shiny disc shaped object.
When I asked him for the shiny disc, he made me say “Please”. After he gave it, he made me say “Thank you”. I found that odd.
When I got home, I remembered uncle’s strange words so I asked dad about them:
“Dad, why did Uncle make me say please?”
“Well, it is a form of politeness. We say please when the person has no obligation to do what we ask. It also makes your request sound less like an order or command.” 
“I see. And then why did I say thank you?”
“We say thank you to let the person know that we are grateful for what they did for us.”
“I understand now. So can I please have some nuts?”
“Of course you can.”
“…Thank you!”