…when they knew God, they glorified Him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. – Romans 1:21

And let the peace of God rule in your hearts, to the which also ye are called in one body; and be ye thankful. – Colossians 3:15

If your spirit is not sweetened by the adoration and the love of God, it will grow bitter. If love does not reign, hate will rule. Look at unthankful people. Hear them talk. Nobody’s character is safe. There is no neighbour whom they will not slander. There is no Christian man whom they will not misrepresent. The very angels of God would not be safe from suspicion if they lived near to people of that kind. But when you glorify God as God, and are thankful for everything-when you can take up a bit of bread and a cup of cold water, and say with the poor Puritan, “What, all this, and Christ too?”-then are you happy, and you make others happy. A godly preacher, finding that all that there was for dinner was a potato and a herring, thanked God that he had ransacked sea and land to find food for His children. Such a sweet spirit breeds love to everybody, and makes a man go through the world cheerfully. If you give way to the other order of feeling, and do not glorify God, but quarrel with Him, and have no thankfulness for His mercies, then you will suck in the spirit of the devil, and you will get into Satan’s mind, and be of his temper, and by-and-by his works you will do. Oh, brothers and sisters, dread unthankfulness! Perhaps you did not think that it was so bad, but it is horrible! God help you to escape from it! ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1763.cfm