Feeling happy and hopeful is like being high up or like moving upwards. Feeling sad and unhappy is like being low down or like falling.
The news lifted her spirits.
Things are looking up.
My spirits rose when I got her letter.
I’ve been walking/floating on air ever since.
I was over the moon when they told me.
I felt as high as a kite.
She’s on top of the world/on cloud nine.
I was in seventh heaven.
I feel really down/low about it all.
He’s in very low spirits.
He’s in the depths of despair.
My heart sank when I saw him.
They looked very down in the mouth/down in the dumps.
Happiness and hope are like bright light or bright colours. Sadness and lack of hope are like darkness or dark colours.
The future looks very bright/rosy.
She brightened up when she heard the news.
His face lit up when he saw them.
They had shining eyes and beaming/dazzling smiles.
The bride looked radiant.
You have to look for the light at the end of the tunnel.
He was in a black mood.
I was feeling blue.
There’s no point in having these dark thoughts.
His face darkened.
They led a grey empty existence.
I’m afraid the outlook is very gloomy/bleak/dismal.
The news cast a shadow over the evening.