Get hold of the wrong end of the stick

完全誤會了意思

使用手扙或拐杖等,如果拿錯方向,便不好使用。

所以這是比喻完全誤會了意思或動機。

eg. Now I understand his intention was good. Yesterday, I got hold of the wrong end of the stick and i rejected his offer. I think I have to apologize for my rudeness.