Beat (one's) breast phrase
To make an exaggerated display of sadness, guilt, or anger about something or that one is pretending to do so.
As soon as John got an unsatisfying test score, he beat his breast in front of the whole class.
Instead of sitting there and beating your chest about an unsatisfying test score, you'd better study harder.
Mary just beat her chest about how much she missed her ex after breaking up, and then the next day, they saw her walking in on the arm of another man.
Once something has been done, you can do nothing but face the consequences.
It is useless regretting about past events that cannot be changed.
Used when one has had time to clearly or objectively think about something that had happened, and they often feel sorry or ashamed about it.
Having an unhappy, disappointed, or ashamed expression
One loses all purpose, hope and confidence of life.
The verb "beat" must be conjugated according to its tense.
The phrase derives from older times, when people would actually do it.