Lost the plot

Lost the plot: one that can actually be discerned by examining the words themselves. To ‘lose the plot’ can mean either to become angry and/or exasperated to a fault, or in a derogatory – if slightly outdated sense – to mean someone who has become irrational and/or acting ridiculously.

• When my girlfriend saw the mess I’d made, she lost the plot.[Quando minha namorada viu a bagunça que eu fiz, ela perdeu o controle.]

Fonte: LifeHack