A common theme I have come across in novels that I have been reading lately is a protagonist's, and hence author's, identification of and struggle with personal vanity.  I too struggle with personal vanity (Is it vain to group myself with successful authors?...yes), although most of the time it does not strike me as struggle, for I largely keep it to myself....at least I think (vain).  I speculate that the more one thinks and ponders (I think and ponder often) the more one is prey to vanity attacks. I say this because the more a person meditates within himself the more secluded he becomes in his own consciousness, thus the more pervasive the "I" factor in his sensory apparatus. Dissociation from the "I" factor is supposedly possible, with concentrated meditative effort, and with benefit. Perhaps the I factor simply warms to me, however, and I would do wise to it retain (vain).

John's personal deadly sin - Vanity.

There are seven:  Sloth, Lust, Gluttony, Vanity, Avarice, Wrath, and Envy.  What's yours?