But God prepared a worm at dawn the next day, and it chewed on the vine, so that it withered.
This worm struck effectively against the very source of Jonah's great gladness, which, strangely enough, was not connected in any way with the great repentance of Nineveh, but was derived from a wretched gourd vine which provided him shade!  If there was ever an example of a man's being "exceedingly glad" for the wrong reasons, here it is in these two verses. There are millions of Jonahs everywhere in our society today, people who are glad, exceedingly so, for the comforts and luxuries they enjoy, rather than for the great hope of the soul's eternal redemption in Jesus Christ our Lord.  They are more thankful for sports contests, outings on the beach, air-conditioning, soft drinks, plenty of beer, etc., than they are for the right to worship God without molestation.  Yes, there are a lot of Jonah's who are still "exceedingly glad" for gourds!