To do something that has no point
Go on a wild goose chase
Very expensive
Costs an arm and a leg
To stop working
call it a day
Not saying what you really mean
Beat around the bush
To get out of control
Out of hand
Believe what people do and not what they say.
Actions speak louder than words.
Get it over with, doing something you don't want to do, but know you have to.
Bite the bullet
Ignore someone
Give the cold shoulder
Believe what someone tells you
Benefit of the doubt
Don't count on something happening until it has really happened
Don't count your chickens before they hatch
Take on a project or task that you can't finish
Bite off more than you can chew
Tell a secret
Let the cat out of the bag
Tell me what you are thinking
A penny for your thoughts
Doing a poor job in order to save money or time.
Cut corners
Go slowly
Easy does it
Something very common
Dime a dozen
Start a conversation with someone new or to make people feel more comfortable
Break the ice
A picture may be better than words
A picture is worth a thousand words
To be treated the way you have been treating others (in a negative way)
Get a taste of your own medicine
Being patient
Good things come to those who wait