I work in 911 dispatch, I already had a pretty dim view of humanity coming into it and being prepared for the unexpected is basically the job description, so not too much has truly surprised me, caught me momentarily off-guard, sure, but not really surprised
Probably my biggest surprise is how few calls I get about foreign objects stuck in various orifices. I definitely thought that would be a bigger thing, but I guess most people choose to suck it up (phrasing?) and drive themselves to the ER out of embarrassment.
Also, overall, little kids tend to be pretty great 911 callers. I don't particularly like kids in pretty much any other situation, so that was surprising to me, but kids listen to me, answer my questions, don't beat around the bush and just blurt things out, and overall tend to be respectful. There's outliers and exceptions of course, but overall some of my favorite callers are little kids.