This is the day the Lord has made; we will rejoice and be glad in it. Psalm 118:24
Suffering eventually touches us all. And in times of difficulty, thankfulness is usually not our first response. But I think God looks at us with pleasure when we find reasons to be thankful (1 Thess. 5:16-18). As we realistically look for the good despite our bad circumstances, we can be grateful that God is holding us close. It is when we trust in His goodness that we find gladness - Kasper
Thankfulness finds something good in every circumstances.