Answer:
When you are inside me you will be encouraged to slam other cars.
The warmer I am, the fresher I am. What am I?
You cannot keep me until you have given me. What am I?
I am round. I have only one line. Circle is not my name indeed. What am I?
The more you add the less it weighs. What is it?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.