bet on the wrong horse 趾高气扬；估计错误；看走眼了

【例句】
Oh man, I bet on the wrong horse! I thought Yankees was going to win the world series with Wang around.
哎唷喂呀~我估计错误！我以为今年洋基队有王建民就可以赢得世界大赛。

He expected Stevenson to be elected President in 1952 but as it happened, he bet on the wrong horse.
他预料斯蒂文森会于1952年当选总统，可结果他完全估错了。