Down to earth people could be important members of society. But they do not consider themselves to be better than others who are less important. They do not let their importance "go to their heads." Someone who lets something go to his head feels he is better than others. He has a "big head."朴实者可能是社会精英,但他们并不认为自己比普通人更优越,不会被自己的重要地位冲昏了头脑(go to their heads).那些被某些东西冲昏头脑的人会认为自己比他人优越,妄自尊大(big head).