感时花溅泪恨别鸟惊心
[găn shí huā jiàn lèi hèn bié niăo jīng xīn]
This originates from a classic Chinese poem. In times of hardship or when feeling sentimental, you feel as though flowers shed tears. When filled with sorrow about separation, birds seem agitated, as if they are also sad. It vividly illustrates intense emotions under special circumstances.