Gratitude is proactive. A thankful person doesn't wait for something good to happen to be grateful toward God. A thankful mindset is aware of all that God has already done in Christ. True thankfulness gives thanks in all things because it knows that no matter what happens, we have a hopeful future in eternity with our Father in Heaven.

Unthankfulness will lead you to the hardness of heart and unbelief, which will limit what God can do through you and for you. This is the hard lesson learned by most of the nation of Israel that wandered in the desert for 40 years.