I suppose those used to riding in chain gangs have non-standard ideas about how much space you need between cyclists. Not that that's an excuse, as it's one thing getting up close with someone you know and trust, and quite another doing it to randoms out on the road who might be daydreaming or easily spooked or whatever.
Anyway today's bonkers incident wasn't a close pass, it wasn't even the oncoming car playing chicken with me on the wrong side of a traffic island in order to overtake some slower cyclists in the other direction, *or* the driver of the car behind who did the same thing into a non-existent gap under they-could-go-therefore-it-must-be-okay-for-me-to-go rules. No, it was the one who was so busy alerting me to the fact that I was riding an unusual-looking bike by applying a blast of horn mid-overtake that they almost failed to notice the van in front slowing down, or the oncoming horse (which at this point had already started to get twitchy about my presence) that it was slowing down for. Fortunately the van blocking the view seemed to calm the horse, and disaster was averted. The horseist rewarded me with an extremely posh "They just don't give a shit, do they?" as I passed with care.