Great cry and little wool.

A great deal of noise or excitement may produce very little of value. The proverb contrasts the scale of the commotion with the smallness of the result.

It can also temper expectations when a promising announcement or elaborate effort ends with a disappointingly modest outcome.

Use it to comment on a gap between the attention an undertaking receives and what it delivers. It works best after the result is clear, rather than as a prediction that an effort will fail.