Answer:
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
I am a fire's best friend. When fat, my body fills with wind. When pushed to thin, through my nose I blow. Then you can watch the embers glow.
They belong to me; they belong to you; They can make you feel happy or make you feel blue; They never end until the day you do.
It's in your hand though you can not feel it. Only you and time can reveal it.
The warmer I am the fresher I am.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?