Many people continue drinking and driving despite strict laws. The gerund phrase in this sentence is acting as subject
direct object
appositive
object of the preposition
predicate nominative

The main character in " The Happy Man" treats his rival with the utmost politeness after waking up happy. Underneath his sense of peace, the author is alluding to the main character's FULFILLMENT. 

The main character in "The happy man" woke up happy. He is so happy that he worries about his happiness. He wanted to know the reason behind his happiness by going to the doctors. In the end, he simply accepted that he is a happy man and continues living as such.

Happy people are usually fulfilled people. They are grateful for what they have in life and they are living examples of self-acceptance.