The traits that irritate us most in other people are often strangely specific. The same flaw in two people can land completely differently — one we shrug off, the other we can't stand. The difference is usually in us, not them.
What we can't tolerate outside is often what we haven't made peace with inside — the impatience, the neediness, the showing-off we quietly fear in ourselves. The other person just holds up a mirror, and we resent the reflection.
Not always — sometimes rude is simply rude. But when someone irritates you out of all proportion, it's worth a quiet look at what they're reflecting back.