A newly arrived soul in Heaven was met by St. Peter, and he took him on a tour around Heaven. They walked inside a large workroom filled with angels working. St. Peter stopped and said, "This is the Receiving Section. Here is where all the prayer requests to God are received". The soul looked at the section, and it was terribly busy with so many angels sorting out prayer requests from all over the world.
They walked again until they reached the next section, and St. Peter told the soul, "This is the Packaging and Delivery Section. Here is where the graces and blessings the people asked for are packed and delivered to the persons who asked for them" The soul noticed there were just as many angels working in that room.
Finally at the next section the soul stopped, and to his surprise there was only one angel there basically doing nothing. "This is the Acknowledging Section," St. Peter told the soul. "How is it that there is no work here?" "That's the sad thing”, St. Peter answered. "After the people received the blessings very few send their acknowledgments". "How does one acknowledge God's blessing?" "Simple”, St. Peter answered. "Just say, “'Thank you, Lord'."