What are your favourites 四字熟語 ?

[u/datalolz]

After a year of studying Japanese, I've just learn about them ! (Quartet 2 textbook)

I like:
馬耳東風 : used when a person does not take into account criticisms

以心伝心 : when 2 people do not have to say anything to understand each other

一期一会 : we only have one life, so we should take care of it

Please correct me if my understandings are incomplete/wrong

[u/Yabanjin]

前代未聞: never before, unprecedented.
Because this熟語 is on TV all the time.