It's raining cats and dogs

It's monsoon season here in East Coast of Peninsular Malaysia. When I'm thinking of rain, I'm thinking of an idiom it's raining cats and dogs to describe heavy rain. What I'm thinking was (at that time) , a group of cats and dogs, quarelling while they were falling off the roof. Funny isn't it? Well idioms are full of funny (and crazy?) synonyms but not all of them. I heard one of them since my secondary school years, hustle bustle. Then, my teacher said "It's too english for you!". All of us didn't get the correct answer for that particular fill in the blank question. Oh well. Now as a worker talking and writing in English for most part of my work, I still rarely use lots of them.