A fictional self

Chapter 9 endnote 33, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:

Whenever you crave material things like expensive cars and clothes, or desire compliments to enhance your reputation, or seek positions of status and power to benefit your life, Buddhism says you are treating your fictional self as real (reifying the self). These material concerns may bring immediate gratification and pleasure but they also entrap you, like golden handcuffs, and cause persistent suffering, which we would call prolonged unpleasant affect. [...] Buddhism refers to self-affirming possessions, compliments, etc., as “mental poisons.” Not only do they cause you to suffer (e.g., feeling like an imposter), but also you feel the urge to harm anything that might invalidate you or threaten to unmask your fictional self.

In case you are unsure of what a fictional self looks like, let me give you an extreme example. In early December of 2014, Cho Hyun-ah, the head of in-flight services for Korean Air, was in the first class cabin of Korean Air Flight 86. The flight was taxiing at Kennedy International Airport in New York City, bound for Incheon, South Korea when she ordered it to return to the gate. Why? To kick off the chief steward, because he'd served her macadamia nuts in an unopened package instead of on a plate.

Ms. Cho, who is the daughter of the chairman of Korean Air, was verbally abusive and violated several aviation laws over a packet of nuts. Her photo appeared in the New York Times on December 12, 2014, with her head bowed in shame.