aim at the moon 痴心妄想,想入非非

【例句】
He was so good-looking and so popular that I felt I'm aim at the moon.
他英俊潇洒招人喜欢，我觉得自己配不上他。

Down to earth, don't always aim at the moon!
脚踏实地地干，别总是想入非非。