Food
Piece of cake
Something that is easy to do
To feel blue
Feeling sad
Hold your horses
Slow down
Keep an eye on
Watch over something or someone
To suddenly feel scared to do something
A couch potato
A lazy person who sits around all day
Tickled pink
Feeling happy
Butterflies in my stomach
To feel nervous
When pigs fly
Never gonna happen
Smart cookie
An intelligent person
To see red
Feeling angry
Raining cats and dogs
Raining a lot
It cost an arm and a leg
Put a sock in it.
Be quiet
Very relaxed/chill
Green with envy
Feeling jealous
"I'm all ears."
To be fully listening
Hit the hay
Go to sleep
To spill the beans
Tell a secret
A golden opportunity
The perfect chance
Copycat
Someone who copies someone else
A pain in the neck
Something or someone that annoys you.
To be in hot water