What does it mean to crush a camel with straw?

This seems to be a western proverb, which means that camels are at a loss. At this time, as long as you put a straw on it, it will crush it. Explain that things have reached the critical point of the limit, and adding any factor will make it collapse. There is an article in college English intensive reading that someone went far away to apply for a teacher, and the results along the way, coupled with the situation during the interview, made him feel very bad and depressed. Finally, the headmaster of the school made a request, so that he couldn't stand it any longer and left. At that time, this proverb was used to say that the last request made by the principal was the last straw on the camel. In the context at that time, it meant that he couldn't stand it any longer.