Off one's rocker

To get angry, frustrated, or irritated to the point that you suffer a tantrum of sorts

Anna: How was tennis, Tim?
Tim: Rubbish. I lost to Aidan. I should try and keep a level head and not go off my rocker when I play...
Anna: Yes. One should never go off one's rocker. Now it's time to eat some squirrel pie.
Tim: :l

by TimkinsTheTimTam December 30, 2011