get off high horse
get off (one's) high horse
To stop acting as if one is better than other people; to stop being arrogant or haughty. Sam is never going to make friends here until he gets off his high horse and stops acting like he knows more than all of us. You're just an intern, so get off your high horse and do this filing, like I asked you to.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
get (down) off one's high horse
Fig. to become humble; to be less haughty. It's about time that you got down off your high horse. Would you get off your high horse and talk to me?
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.