Happiness and joy are a natural result of gratitude.

Happiness and joy do not arise from nowhere. They become a natural result of gratitude.
Gratitude is a conscious decision. The embodiment of the best example of gratitude was Jesus – the Messiah, who taught that the more we strive to fulfill God’s will, we will see that, in addition to everything else, God’s will is also for us to be grateful so that our joy also grew and improved.

   "It was I (Jesus Christ) who told you that My joy may be in you, and that your joy may be full!" From John 15:11

The grace of God the Father revealed in Jesus is a daily source of eternal gratitude.
This is not some temporary fun, excitement, or excitement, but an abiding joy that we can always rely on. True spiritual happiness is based on faith in the Lord.
This is not some fleeting state of euphoria, it is something much deeper and longer – it is joy.
When a person dedicates his whole life to you, it can’t help but please. When a person sacrifices everything he has for you, it can’t help but make you happy. Knowing that the Messiah dedicated His whole life to us and sacrificed Himself for us is not just one of the reasons for joy, it is the most important reason for joy!

In the book of the prophet Isaiah, the 54th chapter begins with the story of a barren woman who suddenly begins to sing for joy.
This means that the state of happiness is the result of a choice. The barren woman had a choice: either fall into depression and self-flagellation or rejoice in her fate. In other words, she chose to be grateful. Perhaps we grew up in a family where everyone was constantly complaining about something, or we tend to be critical of everything, and therefore our first natural reaction to everything is to grumble and complain. But even this is our own decision – to poison ourselves.
This shows that we are not in control of our feelings, but we allow them to control us. Happiness is a choice, a choice to be content with our lot, a choice to be grateful for every moment we are given. Happiness does not arise by itself, happiness is a conscious choice that we have to make.

The Apostle Paul pleaded with the Philippians:
“Rejoice always in the Lord; and again I say: rejoice” (Philippians 4: 4)

 If the state of happiness did not depend on us, and if it were not a decision we are called to make, Paul would not have warned the Philippians to make their own choice in favor of happiness. There is no doubt that the apostle himself considered the state of happiness to be a decision, which is why he urged them to make this decision - to rejoice!
And not only them - always rejoice!

Grumbling and complaints are our greatest enemy, which eats away at our joy.
The main enemy of gratitude is complaints or complaints. That is why the apostle
Paul warns the Philippians:
“Do all things without grumbling or doubting” (Philippians 2:14)
Peter echoes him:
“Be hospitable to one another without grumbling” (1 Peter 4:9)
Yakov joins them:
“Do not grumble, brothers, against one another.” (James 5:9)
Jesus is the perfect role model. He Himself had to go through the most terrible thing that can be imagined: inhuman suffering and painful death. Jesus did not grumble or complain about his bitter fate, and even while dying, he cared for others:
Jesus said: “Father! Forgive them, for they know not what they do” (Luke 23:34)

  The bottom line is that if we don't make a conscious decision to be happy, we will end up, by default, in a state of unhappiness. Why? Because your back hurts, you ran out of money, your boss gets you, you couldn't find a parking space, you have to give in to your desires and do something you don't want to do at all or you just didn't get enough sleep.
  That is why every day of our lives we are called to choose - to rejoice:

“The Lord created this day, let us rejoice and be glad in it!”
(Psalm 117: 24)