Let's look at the person whose demeanor is critical. They are not happy campers! Who or what is it that they dislike? Others and life itself! Some people respond with criticism because they just don't like life. Their existence depends on others unhappiness. Why are people that way? Because they lack love. It's obvious that joy and love are interdependent. One can't be joyous unless they love and they don't love because there is no joy in their hearts.
How are Christians to operate?
Ephesians 4:29 (ESV) "Let no corrupting talk come out of your mouths, but only such as is good for building up, as fits the occasion, that it may give grace to those who hear. "So according to inspired Paul, Christians are to build each other up! That seems contrary to the disposition of the person with a critical demeanor! Why? Because it is! Oh, what are critical people to do? Build each other up! That's not done with criticism. Building up is done by encouraging words:
1 Thessalonians 5:11 ( ESV) "Therefore encourage one another and build one another up..."The last part I omitted: "just as you are doing", because most people aren't doing that nowadays!
How can we encourage? Firstly, by not saying discouraging things, not by rolling of the eyes, not by showing an attitude! Before one can encourage, one must first abandon automatic discouragement! That is your nature! You must change. Fortunately, if one calls on Jesus, change is possible, but people are critical because they may not have Jesus in their hearts. They fail to do the foremost command. They have not loving hearts! Love is hard to do, but it is an obligation because Jesus commands it!
The second thing to do to encourage is "Do unto others as you would have them do unto you!" That's "The Golden Rule"! Do you want others to have a critical spirit with you? Surely not! Even those with a critical spirit don't want to be around others that way! They can't truly stand themselves, so why would they want to contend with others?
With that said, we should treat others well! That's fairness, with meekness, with love and all in accord with God's goodness. That's how you want to be treated. Why not treat others that way?
Thirdly, don't pick at another person. We all are slaves to our own faults. I bet yours are as bad as others! Most people who pick at me, I could destroy with words if that was my demeanor. Mine is to get along and be in accord! Constant criticism is a defense mechanism. It defends a person's inadequacies. Some use this tactic against those who are a threat. It may be education, performance, wisdom, ability or even appearance related. It's jealousy, aka envy.
My former father-in-law had a critical demeanor. There was never a reason to argue or even pay attention to his constant false knowledge and criticism because he was cast in stone. I learned to humor him. I totally ignored his arrogance and negativity because I had to. He was always around! Of course, another course would be to avoid him, but then we would be avoiding most people. I learned the serenity prayer:
I cannot change others. They must change themselves. My role is to have the courage to change the things I can change. In this case, I can't change others, but I can adjust my attitude to ignore their murmurings. Knowing that I'm helpless to change others who don't want to change is wisdom. I know that I can't change for them. All that I can do is pray and ask God to give them a loving heart. Their place is to respond to God. Unless they do, they'll never be happy.
Isn't it sad that people go through life with the motivation of making others miserable? What a goal! Jesus can fix that!