There is an old Persian fable of a hen, a mouse, and a rabbit who lived together in a little house in the woods. They shared all the work and lived in harmony. The chicken found the firewood, the mouse brought the water from a nearby brook, and the rabbit cooked the meals. Each did his work faithfully and contentedly.
Murmuring or complaining is one of those sins that are overlooked. Sometimes we get so focused on the "big sins" such as murder and adultery that we overlook this sin — but the Lord doesn't give this sin a free pass — quite the opposite. It's a hidden killer! This sin unleashed a plague that killed thousands of Israelites! [Numbers 16]
Patience is one of those attributes that you cannot learn by reading about it. It's a quality that can only be acquired by persistent, enduring, practice– and for me it's a drill that I go over, and over, and over again!