Tell me some funny expressions / idioms in YOUR native LANGUAGE!

منذ ٤ أعوام

For Romanian (my native language, that I also teach), my favorite ones are:

- Ca baba si mitraliera ( Like an old lady with a machine gun) : When 2 things/ people don't fit or go along AT ALL

- A vorbi de funie in casa spanzuratului  ( To talk of rope in the house of the hanged) : To  talk of something that could offend those around you without you realizing it.

= A vinde castraveti gradinarului ( To sell cucumbers to the gardener/farmer): To tell a person better qualified or more knowledgeable than yourself how to do their job

What about you? =)