It is our own vanity that makes the vanity of others intolerable to us.

The showing-off that most annoys you is usually competing with your own. A person who genuinely does not care about being thought impressive finds a boaster tedious at worst. The sharp irritation, the one that stays with you afterwards, comes from a claim being staked in territory you also want, which is why it feels less like bad manners and more like an offence.

Next time somebody’s self-display gets under your skin, ask what exactly they are claiming and whether you want it too. The annoyance is a fairly accurate map of your own ambitions, and it is more useful read that way than acted on.