The Apostle Paul says, “Be thankful in all circumstances, for this is God’s will for you who belong to Christ Jesus” (1 Thessalonians 5:18, NLT)
Once again, note that it does not say to be thankful FOR all circumstances but IN all circumstances, knowing that God can work all things, even the worst of things, for good.
Gratitude is always a choice. You have to choose it every single day, sometimes multiple times in the same day. Otherwise, the natural human defaults of entitlement and complaining take over.
I believe the more you practice the art and discipline of gratitude, the more you will see God at work in your life and in your world.