You can give thanks for ALL things!
“Always giving thanks for all things in the name of our Lord Jesus Christ to God, even the Father.” (Eph. 5:20 NASB)
The key
The key to being thankful for “all things” is understanding and believing that God is going to work all things out for you no matter how they may look. Having lived a few decades helps me to see how things, no matter how disastrous they may have looked at the time, eventually worked out to be blessings in disguise. Therefore, I can thank God ALWAYS, in EVERY kind of circumstance whether negative or positive, knowing with full assurance that its all going to eventually turn out as blessings.
“And we know that in all things God works for the good of those who love him, who have been called according to his purpose.” (Rom. 8:28 NIV)
Therefore ..
“I will give thanks to the LORD because of his righteousness; I will sing the praises of the name of the LORD Most High.” (Psalm 7:17 NIV)