the grass is always greener on the other side 这是句谚语 请问是什么意思？

The grass is always greener/这山望着那山高

和这个惯用语基本相当的中文说法是“这山望着那山高”。意思就是说得不到的总是看起来更诱人一些，总是比已经拥有的好。常常只说The grass is always greener,而省略后面的on the other side of the fence.
比如说，刚开始你觉得没男朋友挺好，自由自在，but when you haven’t been out for a while you may start to envy of Grace’s dates with her handsome boy. :-) Oh well, the grass is always greener.是不是呢？

Example Dialog:
Sandra: How are things going with your new job?新工作做的怎么样？
Lisa: Not bad. But not as wonderful as I’d expected before I secured it.还不错。但没我上班前想得那么好。

Sandra: Well, I understand that. You know, the grass is always greener.是啊，我理解，还没得到一件东西时总觉得它很诱人。