Idioms
Lighten up
to relax
all smiles
looking very cheerful and pleased
under the weather
to feel sick
Piece of cake
really easy
Blow off steam
to get rid of strong emotions
Speak of the devil
The person we were just talking about just showed up
Are you pulling my leg?
Are you messing with me?
Cutting corners
to do something poorly in order to save time/money
drop your guard
to stop being careful about showing your emotions.
cost an arm and a leg
being extremely expensive
Raining cats and dogs
raining really hard
Rule of thumb
a well-known rule/practice based on experience
to see red
to get really angry.
Call it a day
to decide to stop doing something
to burst into tears
to suddenly start to cry.
wrap your head around something
to fully understand something
Get a grip
to get control over your emotions.
Keep a straight face
to try not to smile or laugh.
Lose your head
to lose control of your emotions.
hit the hay
go to sleep
Break a leg
Good luck
a dime a dozen
something very common
A picture is worth a thousand words
better to show than tell
Go back to the drawing board
to start over
Wear your heart on your sleeve
to show your emotional feelings all the time