What am I? riddles about everyday things

I have many teeth but I never bite.
Every morning I walk through the forest on your head.

After your bath I drink what the water left behind.
The more I help you, the wetter I get.

I copy everything you do without a sound.
Raise your right hand and I raise my left.

I am tall when I am young and short when I am old.
I shed tears of wax while I work.

I am small and my teeth are made of metal.
Without me, your own door treats you like a stranger.

I sit in one corner,
yet I travel all over the country.

The more I work, the shorter I become.
Sharpen me and I am ready to work again.

I am soft and I listen to all your dreams.
I never tell anyone what I hear.

I have steps but I am not a house.
I help you reach high places and then go back to lean on the wall.

I have one eye but I cannot see.
A long thread follows me wherever I go.

My door is opened a hundred times a day.
Inside me it is always winter.

I whistle, but not because I am happy.
When I whistle, the dal is nearly done.