Riddles

My daughter wants to tell me riddles all the time.... the problem is, she is the WORST riddler ever. 

For example:

"Mommy, guess what is green, has petals, and grows in the ground?"

"What?"

"A flower!"  

Or this happens:

"Mommy, guess what has a trunk and four legs?"

"What?"

*hysterical giggles* "I can't tell you!"

So I've tried to teacher her what a riddle is.  I've given her examples. 

Q: What has 4 legs but can't sit down?
A:  A table!

Nothing has stuck.  And then today I thought she finally got it.  I got this:

"Mommy, what is all around us but we can't see it?"

"Um, air."

I got the riddle right.  However, I was wrong about her getting how to tell riddles, because her response was the funniest answer I've ever heard: 

"MO-OM!  It's not fun if you get it right the first time!!"