get on one's high horse 高高在上；趾高气扬；态度傲慢；盛气凌人；怒气冲冲

【例句】
The minute you start arguing, you get on your high horse. You just can't help yourself, can you?
只要一开始争论，你就会摆出一副高高在上的样子，好像跟你意见不同的人都是傻子似的。你就是控制不了你自己，对吧？

He likes to get on his high horse and judge others by his own standards.
他喜欢摆出高高在上的姿态，用他的标准来评断别人。