Back to the drawing board
When something doesn't go well and you need to start over
A penny for your thoughts
Tell me what you are thinking about
Let sleeping dogs lie
Stop talking about an issue
Back seat Driver
When a passenger tells the driver how to drive and what to do
Call it a day
Stop working on something; finish
A blessing in disguise
Something good that seemed bad at first.
Easy does it
Slow down
It takes two to tango
It's not just the responsibility of one person; it takes two or more
Don't give up your day job
You're not very good at something so don't make it your career
Cup of Joe
A cup of coffee
You can't have your cake and eat it too
You can't have everything
Seeing eye to eye
Agreeing with each other
You can lead a horse to water but you can't make him drink
You can't force someone to do something
Don't count your chickens before they hatch
Don't count on something happening until it's actually happened
Take a rain check
Postpone something
Through thick and thin
In good times and bad times you stay together
Every cloud has a silver lining
Good things come after bad things
Don't put all your eggs in one basket
You need a variety; don't have all the same thing
Comparing apples to oranges
Trying to compare things that are not the same
Hit the sack or Hit the hay
Go to sleep
Baker's dozen
Although a dozen is 12 items, a baker's dozen is 13 items
Cutting corners
Doing a bad job on something to save time or money
When it rains, it pours
Everything is going bad at the same time
A snowball effect
Events that keep building on each other
On cloud nine
When someone is very happy
The pot calling the kettle black
Criticizing someone else even though you do the same thing
Don't burn bridges
Don't ruin a relationship (you might need it later)
Haste makes waste
You'll make mistakes if you rush and then you'll have to do it over
Dropping like flies
A large number of people getting sick at the same time
Make a long story short
Tell a story in a brief way; don't tell every detail
Beat around the bush
Avoiding saying what you want to say because it's uncomfortable.
Chip off the old block
When someone is similar to their parent
Calm before the storm
Something bad is going to happen but right now all is good
Southpaw
A boxer or baseball pitcher who is left-handed
Do something at the drop of a hat
Do something without planning it
Once bitten, twice shy
You are more cautious when you've been hurt before
Excuse my French
Forgive me for swearing or cussing
A dime a dozen
Something common
Get a taste of your own medicine
Get treated the way you treat others (in a negative way)
It's not rocket science
It's not hard
A perfect storm
The worst possible situation
The elephant in the room
The problem/issue people are avoiding
Best thing since sliced bread
A great invention