What is the ruling on one who complains and grumbles a lot?

A Muslim should frequently praise and thank Allah and speak of His blessings, for Allah Almighty says: "But as for the favor of your Lord, report [it]" and "And if you should count the favors of Allah, you would not enumerate them." As for grumbling and complaining out of discontent, it is a grave danger, for the Prophet (ﷺ) said: "If Allah intends good for His servant, He hastens the punishment for him in this world, and if He intends evil for His servant, He withholds the punishment for his sin until he meets Him on the Day of Resurrection." And he said: "Indeed, the greatness of the reward is commensurate with the greatness of the affliction. And indeed, if Allah loves a people, He afflicts them. So whoever is content, for him is contentment, and whoever is discontent, for him is discontent." As for moaning or weeping that overcomes a sick person or one afflicted due to pain or calamity, along with contentment with Allah's decree, there is no harm in it.