What am I?

I fill you up with hope

I pull you down with sorrow

I make you smile brightly

I make you cry softly

Full of happiness and sadness

I make you so angry

I make you so jealous

Thoughts that aren't true

Depression which can kill

I'm very painful

I hurt you with thorns

I break the strongest of people

Falling down into pieces

You miss me when I'm gone

You then feel all alone

I enjoy your smile

Yet I do not favor

No good nor evil

Question: What do you think it was?