The straw that breaks the camel’s back 无法忍受；压倒骆驼的最后一根稻草

the final insult and unendurable burden  最后一次的侮辱和难以忍受的负担

Example The restaurant had horrible service and an unpleasant atmosphere. When the food came out cold, I decided it was the straw that broke the camel’s back, and walked out.          

例如    这家餐厅的服务很差劲，并且环境也令人不愉快。 当冷的食物被端出来后，我决定再也不忍受了，走了出去。