Thank you notes are a dying art.
Truth be told, with the cultural shift away from letters and notes posted in the mail, one is more likely to get a like in a social media direct message than a formal thank you note...if that. We are caught up in the busy rush going from one urgent thing to another that something as simple as a short expression of gratitude, written or spoken, is passed over quickly as something to be done when we get a spare moment, but that spare moment never comes.
Sometimes, though, that thanksgiving will come, from the unlikeliest of sources. Possibly the cranky black sheep of the family, the stand-offish coworker, someone who is on the periphery. Everyone else is too busy to be grateful, but that one person whom we expect to be ungrateful surprises us all and is full of sincere thankfulness for what is done. It is marvelous. It is a beam of unlooked-for joy. It is the thing that makes all the effort worth it. And it turns our expectations and preconceptions on our ear, showing that preconceptions are nothing more than roadblocks to true understanding.
A couple of thousand years ago Jesus and ten lepers demonstrated this turning of expectation on its ear to His disciples. Our Gospel assignment at Mass (Lk. 17.11-19) tells us of Jesus encountering ten lepers and healing all of them. Only one came back to Him to say "thank you," and it wasn't one of the nine who were of Jesus' tribe and nationality, who were raised to bring thanksgiving to God for what He does for His children. No, this was one of THEM, a Samaritan, someone Jews would have expected to be surly, ungrateful, and rude to the Jewish rabbi. On the contrary, he came back to give proper praise to God for his deliverance, and Jesus made very certain that NO ONE missed that.
Faith shows up in the unlikeliest of places. Thankfulness and praise come from unexpected people. Perhaps that is to teach us humility, to teach us through those we despise that they get the Kingdom of God better than we do, and we would do well to emulate them.