last straw

the last in a series of unpleasant events that finally makes you feel that you cannot continue to accept a bad situation

(压垮骆驼的)最后一根稻草;使人最终崩溃的一击

例：

Losing my job was bad enough, but being evicted was the last straw.

丢了工作已经够糟了，但被房东赶出门后我彻底崩溃了。

A: When he told me I had to work overtime, that was it.

当他告诉我我必须加班的时候，我受够了。

B: The last straw, huh?

你是忍无可忍了，是吗?

A: Yes, he's really pushed me too far.

是的，他对我太过分了。