What is Sasson most famous poem?

There seems to be a misunderstanding. There is no poet named "Sasson." It is possible you are thinking of:

* Siegfried Sassoon, a British poet and soldier during World War I, known for his powerful war poetry. His most famous poem is "Suicide in the Trenches" which depicts the brutal reality of trench warfare.

* George Sassoon, a 20th-century American writer. He is known for his novels, not poems.

Please clarify which "Sasson" you are referring to. If you can provide more context, I may be able to help you find the specific poem you're looking for.