Question

IDIOM: a long joke that often ends in a silly or disappointing way

Accepted Answer

I made some pretence of listening while he told me a SHAGGY DOG STORY, but in reality I was endavoring to think of a good way of taking my leave without offending him.

Front	IDIOM: a long joke that often ends in a silly or disappointing way
Back	I made some pretence of listening while he told me a SHAGGY DOG STORY, but in reality I was endavoring to think of a good way of taking my leave without offending him.

I Idiom Long Joke Ends Silly Disappointing Made