From the Pulpit, it is taught that thankfulness is necessary, not just in saying thank you, but in how we say it. Hello may mean different things by the way it's said
Psalms 28:5 (KJV)
Because they regard not the works of the LORD, nor the operation of his hands, he shall destroy them, and not build them up.
Even when there seems to be no reason, check your records and you will see the doings of God.
Obadiah 1:17 (KJV) But upon mount Zion shall be deliverance, and there shall be holiness; and the house of Jacob shall possess their possessions.
We're blessed not because we are the best but by God's grace of election.
What makes God the God is His Glory thus he will never share his glory with anyone. So give him his glory.
An unthankful man is a proud man. God resist the proud. Pride proceeds the Fall.
Don't allow your heart to be lifted up against God like Nedchardnazzar, Herold, Uzzarial etc