The straw that broke the camel's back

"The straw that broke the camel's back" is an idiomatic expression that refers to a seemingly small or insignificant event or action that triggers a larger, often negative, consequence. It implies that a situation has reached its breaking point, and any additional pressure will cause the situation to collapse or become intolerable. It originates from the idea that a camel can carry heavy loads, but there is a limit to their capacity, and it only takes a tiny additional weight (represented by the straw) to cause the camel's back to break.