The best definition of grumbling, it seems to me,
says simply "to mutter discontentedly."
Protesting against something in a bad-tempered way
is a thing most humans practice each day
and, in most cases, choose a subliminal voice
in stating our objections to an undesired choice.
Grumbling does not require intelligence,
neither a large measure of common sense.
It demonstrates no great ability,
and is common in those with low mentality.
In fact, among grumblers, you will hardly find
a person with a truly open mind.
Great character is never shown by grumbling,
nor will it guide one's path to prevent stumbling.
Never will it call for self denial --
it always is the other man on trial.
Simple grumbling never solves one's problems,
and never leads one to the means to solve them.
Constructive criticism is the way
that can lead to a better and happier day.
Being willing to step forward and state your case
is the best way to see your desires in place.
So, enough of your moaning and groaning and grumbling.
All of these partner with mumbling, stumbling and fumbling.