In the park I sat down to read on the bench,disappointed by

In the park I sat down to read on the bench,disappointed by life with good reason to complain.
后面还有一句：for the world was always letting me down.请问这句话怎么翻译啊?
,disappointed by life with good reason 这句最难翻译，请给出这句的具体意思！谢谢！！！

for 这里是因为的意思,比较书面的说法
意思就是：为什么我disappointed呢?因为这个世界总是让我失望.就是这样：）
对于您的补充的回答：应该是 a good reason 或者是 good reasons吧
对生活失望且抱怨有理.是这个意思