As Melvin, who suffers from acute OCD, is one of the rudest men that waitress Carol has had the misfortune to meet, it seems there's little chance of a happy ending for this mismatched couple.
However, when Melvin's generosity changes the course of Carol and her son's life the relationship between the two blossoms into fantastically mismatched couple heaven.
Lesson learned: You can be as rude as you like as long as you've got dollar or two.