We had a customer last year send a request for our holiday schedules (what days we would be closed or 1/2 days etc.) and there were 75+ of the original 200 or so email recipients that answered with a reply-all.
Naturally, some got upset and started reply-alling for the reply-alling to stop. LOL, it was fun as hell to watch for 3 days as these idiots just kept doing it over and over.