Truth or Play?

What's in a nickname? What is in a playful conversation with your partner? Do names or phrases spoken with the spirit of affection or endearment reveal anything else? Recently, my partner said he would name a book about me called "Angels and Demons." He was quite funny in his presentation, and we both laughed. But was he telling me more than just making a joke? Obviously, he sees a contrasting nature in me depending on the lens he is viewing from, and the mood that I happen to be in at that time.

What else does it mean? Is he telling me that he loves me despite moments of having a "not so pleasant side?" Or he is saying that he stays because the good outweighs the bad? Which brings me to my next question...why do relationships go bad when we understand that humans are complex beings capable of displaying a pleasant and not so pleasant nature?

I recently was reading a book on communication in relationships (Close Encounter by Guerrero, Andersen, and Afifi). It spoke about how our level of attractiveness to another person will either increase or decrease, by whether our expectations are met or not. So if we stay when we are disappointed, is this referring to the brownie points system? Perhaps I should take my partners "term of endearment" seriously, and make sure I keep those brownie points stocked!