They had seen things on their journeys they never would have believed otherwise. They had experienced God's power in incredible ways. They had changed people's lives. And missions trips aren't just exciting for us down here on earth. He feels it all right.
Missions trips can succeed and fail at the same time.
If they'd gotten all caught up in their successes, the trip would have been a failure. Which is exactly what Jesus wanted to prevent. So, when the 72 missionaries came home, Jesus held off on congratulating them. Instead, he shifted their focus back to God. This is no time to pat yourselves on the back, he told them.