What are the motifs in Marley and Me by John Grogan?

Master and beast is a recurring idea in the story. In Chapter Seven, John struggles to establish himself as Marley's master. In typical human ideology, man is the owner meant to teach the pet. However, Marley turns this idea around in his own subtle way. John does not realize that Marley is teaching him important life lessons until he sits back to reflect on Marley's life. In the end, John comes to understand that what most people view as Marley's inability to behave is really his zest for life, refusing to be repressed. Marley is not content to lie quietly in the garage while life passes him by. Instead Marley chases after poodles that catch his eye, eats ripe mangoes until he is sick and greets visitors with unabashed joy. If everyone lived the way that Marley does, they would be able to have more experiences and fewer regrets.