Cry over Spilt Milk

To be upset about something that has already happened and cannot be changed

Ball Is in Your Court

It is your turn to take action or make a decision

Don't Judge a Book by Its Cover

Do not judge something by its appearance alone

Storm in a Teacup

A lot of commotion or fuss about a trivial matter

Bite the Hand That Feeds You

To act badly toward someone who has helped you

Brain Teaser

A problem or puzzle that is difficult to solve