Do all things without grumbling or disputing, (Philippians 2:14, ESV)
I appreciated Tim Challies tongue-in-cheek statement on complaining:
I’m not a grumbler, a complainer, and it’s a good thing, too, because complaining is one of those sins that I find especially offensive. Jerry Bridges counts it as one of Evangelicalism’s “respectable sin,” one that falls under our collective radar. He is probably right. But I’m onto it. I can spot it blindfolded at a hundred yards.
You must know what it’s like to be around those people who always find something to grumble about. Good news comes in and they somehow manage to find the negative spin. Bad news comes and they nod knowingly because this is exactly what they expected to happen. When a leader makes a decision, it is the complainers who begin to murmur, who begin to talk to everyone else, to ask the leading questions. You see them huddled together in the church foyer, you see them whispering together in the cafeteria after the meeting. They’ve got an opinion about everyone and everything and feel justified in being heard far and wide. They are complainers. They are grumblers.
My understanding of complaining is that it typically manifests pride. There is a pride that assumes that you know what others do not, that they have ignored information you believe is obvious, that the church, the world, the business, the family would work so much better, go so much more smoothly, if the leaders stepped back and allowed you to take the reigns. You may not say it quite like that, but isn’t that at the heart of most complaining—that your way is the best way? Do it your way and it will succeed, do it another way and it will fail. That’s at the heart of most grumbling. I hate that sin.
Now, to be fair, I guess I occasionally do some of this. I’ve got an opinion on most things and tend to believe that my way will work better than your way if you will just give it a chance. But that’s not pride, that’s selfless realism. After all, I’ve read lots of books and have experienced quite a bit of what life offers. Here’s the difference between me and you: I’m not complaining; I’m just humbly expressing what is true—that you should give me a hearing and then do things the way I suggest. Even though I may have an incomplete grasp of the facts, I definitely have the most important ones at my disposal and know beyond doubt that you’re wrong and I’m right. I’m not a complainer; I’m a servant! I’m not grumbling to others, I’m just sharing my thoughts and asking them to verify that it’s better than what you’ve suggested.
I’m no complainer! It’s just that I am especially gifted at seeing the facts, putting the pieces together, and charting a forward course. It’s a gift. When you do it you’re sinning, we all know that. But when I do it, I’m expressing love. It’s a spiritual gift in action. When you do it it’s proud grumbling; when I do it it’s humble service. That’s the difference between you and me. And that’s why I find your complaining so offensive. Yeah, that must be it.
Matthew 7:3-5

I recently read some helpful words by Dan Phillips about putting out the flames of gossip before the do their damage.
 
First, understand what gossip is. Gossip is spreading harmful information in an ungodly manner — without love, and thus to no positive end. Its offspring are the triplets: Strife, Dissension, Division. Once again, my focus is the life of the local church [or workplace].Second, do any or all of the following steps, as needed. Some of them help identify whether you're actually hearing gossip or not. All of them will stop it dead. But none will work... unless used.
 

1. Ask, "Why are you telling me this?" Often, that in itself is such a focusing question that it can bring an end to the whole unpleasant chapter. It has the added benefit that it can help a person whose intentions are as good as his/her judgment is bad.
2. Ask, "What's the difference between what you're telling me and gossip?" See above; same effect, same potential benefits.
3. Ask, "How is your telling me that thought, that complaint, that information going to help you and me love God and our brothers better, and knit us closer together as a church in Christ's love?" Isn't that the goal we should share, every one of us? Won't it take the working of each individual member (Eph. 4:16)? Isn't the watch-out for harmful influences an every-member ministry (Heb. 3:12-13; 10:24; 13:12-15)?
4. Ask, "Now that you've told me about that, what are you going to do about it?" While the previous two are subjective, this is not. If neither of the previous two questions succeeded in identifying gossip/whispering/sowing-dissension for what they are, the answer to this question will do so. Tip: if the answer is "Pray," a good response might be "Then why didn't you do that and leave it there in the first place?"
5. Say, "Now that you've told me about that, you've morally obligated me to make sure you talk to ____ about it. How long do you think you need, so I can know when this becomes a sin that I will need to confront in you?" The least that this will accomplish is that you'll fall of the list of gossips'/whisperers' favorite venting-spots. The most is that you may head off a church split, division, harmed souls, sidelined Gospel ministry, and waylaid discipleship. Isn't that worth it?

There is no doubt that the Lord would have us uninterruptedly occupied in this holy meditation; that, while we contemplate in all creatures, as in mirrors, those immense riches of his wisdom, justice, goodness, and power, we should not merely run over them cursorily, and, so to speak, with a fleeting glance, but we should ponder them at length, turn them over in our minds seriously and faithfully, and recollect them repeatedly. -- John Calvin, Institutes of the Christian Religion, Vol. 1, p. 180
Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things. (Philippians 4:8)
I will ponder all your work, and meditate on your mighty deeds. (Psalm 77:12)
May my meditation be pleasing to him, for I rejoice in the Lord. (Psalm 104:34)
On the glorious splendor of your majesty, and on your wondrous works, I will meditate. (Psalm 145:5)
Oh how I love your law! It is my meditation all the day. Your commandment makes me wiser than my enemies, for it is ever with me. (Psalm 119:97–98)
Great are the works of the Lord, studied by all who delight in them. (Psalm 111:2)
Receive instruction from his mouth, and lay up his words in your heart. (Job 22:22)

I really appreciated this article by Thom Rainer:
 By the time we hear of a leadership failure, any attempts at intervention to save the leader are usually futile. The damage has been done. The family or organization suffers as their leader has fallen or, at the very least, made a major mistake.
Most great leadership failures, however, don’t begin with some stupid action. The leader usually has thoughts about the action well before he or she actually makes them. Some of those thoughts can be warning signs to heed. They are like the bright, flashing red light that demands we stop. Failure to stop can result in great harm.
I’ve had the opportunity through the years to listen to leaders talk about their biggest victories and their greatest failures. When the latter takes place, these leaders reflect that, most of the time, the failure took place in a deadly thought pattern. They lament they didn’t recognize these deadly thoughts for the warnings that they were. Here are the seven most significant warning thoughts I’ve heard:

1. “It won’t hurt to compromise a little.” So the numbers get fudged a bit. Or the private meeting with someone of the opposite gender is deemed harmless. Or you take credit for something you didn’t do.
2. “I can give my family time later in life when I’m more established.” You may not even have a family if you wait until later. Few leaders have ever died wishing they had put more hours into work. Many have died lamenting their failure to give their family time and attention.
3. “No one really pays attention to what I do.” Wrong! If you are a leader, many people are watching you more closely than you think. In organizations, those under your leadership watch you closely. In families, the children watch the parents with an eye for detail that can be downright humbling. What are they seeing when they watch you?
4. “I need to be careful not to rock the boat.” Granted, some people put their mouths in action before their minds are in gear. But too many leaders, to mix the metaphor from a boat to an athletic event, play defense and not offense. They are too risk averse. They are more worried about failure than proactive leadership. Thus their thought patterns are almost always about playing it safe.
5. “I can put off that tough decision until later.” Leaders often think difficult decisions can be put on hold. They are involved in “analysis paralysis” thinking as an excuse to defer the decisions. Their thinking leads them to deadly procrastination.
6. “That person messed up five years ago. He doesn’t deserve a second chance.”Many driven leaders shared with me that they failed to demonstrate forgiveness and grace in their leadership role. Their thought patterns focused on the failures of those in the organization or family. They thus “wrote off” these people. When a time came in the leader’s life where he needed an extra measure of grace or forgiveness shown, few people were willing to give him what he himself failed to give.
7. “My main goal is money.” Money is not evil; the love of money is. If leaders’ thought patterns are consumed with money, problems are on the horizon. Money can be an instrument for good or evil. The goal is not to make money, but to make a difference with your money.

I am grateful to be able to hear from leaders who shared with me openly and transparently. What would you add to these seven deadly thoughts?

The heavens declare the glory of God, and the sky above proclaims his handiwork. Day to day pours out speech, and night to night reveals knowledge. There is no speech, nor are there words, whose voice is not heard. (Psalm 19:1–3, ESV) 
 We liked to be awed. We enjoy brilliant Christmas light displays, loud and flashy Super Bowl halftime shows and toys that are bigger and faster. It seems like people (Americans, really) are shouting: "Is that all you've got? Come on, wow me!"
In a way, it's a lot like the Pharaoh of Moses' day. He held the Israelites in slavery in the land of Egypt. Moses was sent by God to call Pharaoh to set God's people free. Moses demonstrated through miraculous signs that the Creator God was behind the emancipation efforts – he turned water to blood and his staff into a snake and still Pharaoh remained unimpressed. These miraculous deeds were followed by the infamous plagues: frogs, flies, gnats, boils – the list goes on. All of them were started and stopped by a command from Moses. And what’s amazing is they didn’t affect the Israelites in the land, only the hardened Egyptians. Yet despite all the mighty displays of God’s power, Pharaoh’s response remained the same:
Still Pharaoh’s heart was hardened, and he would not listen to them, as the Lord had said. (Exodus 7:13, ESV) 
Pharaoh was unmoved by what he saw. God was at work all around him shouting through a megaphone and yet he remained fixed like a pillar, unwilling to open his eyes to that which as on his doorstep.
But how many of us are the same way. God’s creation speaks forth, his wondrous miracles pass through our lives each day and we give them a blink and a yawn. Yet we want something flashy and bright. We want God to give us a sign – just a little miracle and then maybe, just maybe, we could believe.
But look around. The miracles are everywhere. The dazzling displays of his brilliance and power are as close as the snowflakes falling on your nose. They’re in the laughter of a child, the flash of lightning, and a crimson sunset. Take just a moment today and open your eyes and ears to the voice of God all around you and prepare to be amazed.