“In a nutshell”

“Cast in stone”

Fixed and impossible to change.

“Dig your heels in”

To refuse to change your opinion or position.

“Big fish in a small pond”

An important person in a small group or limited environment.

“Follow in someone’s footsteps”

To do the same thing as someone did before you.

“Go down in flames”

To fail completely and dramatically.

“A storm in a teacup”

A lot of anger or worry about something unimportant.

“Go in circles”

To make no progress while repeating the same ideas or actions.

“In a pickle”

In a difficult or troublesome situation.