I don't mean to put any composers out of work, but many works that promise great things simply do not need to be written.
He smiled, and just the smile promised painful, unpleasant things.
They'd stumbled very eagerly, taken his money, promised impossible things.
He put himself under the care of a medical man, who promised great things, and made him endure severe bodily pain, without any good results.
Like explaining about being polite to people, and why you shouldn't promise things without knowing what they are first.
"I was promised wonderful things if only I would do this film."
"Lots of people promise things that don't come true," she explained.
I, too, could promise things, but you expect results that can be seen.
Those who promise great things do not always match up to their own or anyone else's expectations!
I learned early on, don't promise things you're not sure you can deliver.