I believe the novella is the perfect form of prose fiction. It is the beautiful daughter of a rambling, bloated ill-shaven giant (but a giant who's a genius on his best days).
Writing an informative yet compact thriller is a lot like making maple sugar candy. You have to tap hundreds of trees - boil vats and vats of raw sap - evaporate the water - and keep boiling until you've distilled a tiny nugget that encapsulates the essence.
Short stories are my favorite art form. A good one is compact and complete, a telling little slice of life, capturing a moment in time that - for the character - defines her, changes her, is the tipping point for all that will follow.
It is not a great Xerxes army of words, but a compact Greek ten thousand that march safely down to posterity.
'Dune' was like a giant machine, and it was hard to keep track of all the pieces, but 'Blue Velvet' was a very sleek, compact little experience.
My favorite form is the short story. From an aesthetics stand point you really have to pare down to the bone. You can't write a throw-away scene.
I write novellas because I don't like loose sprawling prose.
I write short, my words tight to the thread of the narrative.