What is the deeper meaning behind this verse (Jonah 4)?

God showed Jonah that he had more pion about a gourd that he had nothing to do with, than for the city of Nineveh, a huge metropolis of the day. Jonah was prepared to give up on all those people and let them die, but God had a job for him to do on their behalf. God could easily have said, "Okay, you've had enough of them? Fine. One scorched earth, coming up." But, He took the time to show Jonah a better way. What part of this don't you get?