忘乎所以 [- hū suǒ yǐ]forget oneself; become delirious with joy; forget everything in one's joy; get a swelled head; (They) grow so swellheaded and conceited that (they) simply forget themselves.; have one's head in the clouds; lose all bearings in moment of pride and satisfaction; make sb. swellheaded; one's head has been turned (by ...); turn one's head:•¶ 心血来潮，忘乎所以 be carried away by a sudden impulse; lose one's head in a moment of excitement
•¶ 在胜利面前不要忘乎所以。 One mustn't be carried away by one's successes.