Best of British Slang - To go off on one.
"To go off on one" is an idiomatic phrase that means to suddenly become angry or agitated about something. This phrase is usually used in informal situations and when someone is loudly and strongly expressing their anger or frustration about something.
For example:
I tried to explain the situation to the customer, but he went off on one and threatened to make an official complaint.
my mum completely went off on one when she got home from work.
Sorry for going off on one. I've had a bad day, but i shouldn't have taken it out on you.
