Simple riddles

When you have me, you feel like sharing me. But, if you do share me, you don't have me. What am i?

When I look at her, she smiles at me. When I wink at her, she winks at me. When I kiss her, she kisses me back. When I say I love you, she says it back. Who am I?

I look flat, but I am deep, Hidden realms I shelter. Lives I take, but food I offer. At times I am beautiful. I can be calm, angry and turbulent. I have no heart, but offer pleasure as well as death. No man can own me, yet I encompass what all men must have.

What can go up a chimney down but not down a chimney up?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth I am dissolved into air. What am I?

I am seen in the water if seen in the sky, I am in the rainbow, A jay's feather, And lapis lazuli.

What can be swallowed, but can also swallow you?

There is something which arrested for attempting but not for completing. What is it?

In a supermarket, the first 25 customers of the day purchased an average of two items each. After a further 15 customers, the average number of items purchased by each customer rose to eight. What was the average number of items purchased by the last 15 customers only?

If I drink something, then I am just over. However, I can eat anything. What Am I?