I don't endlessly deliberate if I should reshape my nose or dye my hair or wax my back. I don't slather myself with moisturisers and perfume and exfoliants. I don't dwell over every detail of my behaviour. I don't swell with pride over my achievements or wallow in self-pity over my failures. I don't hold forth about every ongoing personal saga. I don't imagine I'm astonishingly talented or charismatic.
Of course a bit of self-analysis and self-awareness is essential if I'm to relate intelligently and considerately to others. Those embarrassing individuals who never examine themselves and have little insight into their own motives or the messages they're sending out are already too numerous.
But those tiresome me-worshippers who find their own existence far more fascinating than the trivial lives of anyone else are pretty infuriating.
Every so often I have the misfortune to be at a social gathering where one self-absorbed guest is blathering on about the ins and outs of their humdrum everyday life as if every detail is front-page news, while the other guests listen politely and wonder how long this interminable monologue might last. If they manage to interrupt the flow for long enough to broach a change of subject, Mr or Ms Aren't-I-Wonderful will either find some personal slant on the new topic or ignore it altogether.
If anything, I'm the opposite of narcissistic, I tend to be too self-effacing and too intrigued by other people's conversation to make a proper contribution of my own. I find my life fascinating but I'm never entirely convinced that others might think the same. I need a lot of persuading that people actually want to know about me and my tangled personality. I'm quite capable of lengthy silences if I'm not totally confident of other people's genuine interest.
Apart from anything else, it must take so much effort to be narcissistic. Constantly talking yourself up, screening out criticism, tweaking the unflattering reality into something more impressive. You can't let up for a moment, or the mask will slip and the mere mortal will re-emerge. Unthinkable!

