Wake up calls are strange

Why do people lie when somebody calls in the morning?

*ring ring* .... *ring ring* .... *ring ring*

me: "Hi.. What's up?"

caller: "Sorry did I wake you up?!"

me: "No no no. I was just lying in the bed and chilling.."

Why do we always have to lie instead of just saying:

"Yes you did wake me up but it's cool. What's up?"

or: "Yes you did. Call me back when the sun comes up!"