(Don't) Cry over spilled milk
(Don't) Be upset over something that has already happened and cannot be changed
A couch potato
A couch potato refers to someone who spends a lot of time sitting on the couch, watching TV.
Cost an arm and a leg
Very expensive
When it rains, it pours
When something goes wrong, everything goes wrong.
Catch someone red-handed
To catch someone during crime commitment or doing something wrong
On cloud nine
Being on cloud nine indicates a state of extreme happiness or euphoria, often resulting from positive emotions or experiences.
A bad apple
A person who creates problems or is a bad influence on the other people in a group.
Rule of thumb
A general, unwritten rule learned from experience
Go with the flow
Allow things to happen and accept them as they are.
Break a leg
Good luck
Be in the same boat
Being in the same boat means sharing a similar situation or predicament with others, usually involving common emotions or challenges.
Have a sweet tooth
Like eating cakes, candy and other sweet-tasting food.
Keep your chin up
Stay positive and not let difficult circumstances get you down
Down to earth
To be modest, practical, unassuming and unpretentious
Call it a day
Stop working on something
Get over something
No longer worry about something and it no longer let it affect you in a negative way.
Also Get something out of your system
Compare apples and oranges
Consider different sorts of things the same.
Play it by ear
Respond to a situation as it develops without having a plan.
The tip of the iceberg
There’s a lot more going on than what’s immediately visible
Get out of hand
Become uncontrollable, chaotic
Be/Feel under the weather
The phrase “under the weather” is used to describe someone who is feeling sick or not well.
A piece of cake
A task or job that’s easy to do, like eating a delicious piece of cake!
Put one’s foot in one’s mouth
Say something unintentionally embarrassing or tactless.
Between a rock and a hard place
Faced with a choice between two equally unsatisfactory options
Speak of the devil
Speak of someone, right when they arrive