Fun stuff I had to deal with include: The admin's "Anti-Evil Operations" frequently deleting user comments with no explanation. A persistent pedophile who just wouldn't go away. Getting guilt tripped by a severely mentally ill guy whenever we had to ban him (and his many alts) for breaking the rules. Doxx. Gore. Brigading. White supremacists. Racists with their "racial crime statistics". An impossible to moderate Reddit Chat (there were no chat moderation logs at all). And much more.
I completely checked out of moderation when I remembered that I wasn't getting paid to deal with any of the above. And since then, I've had much more appreciation for all the moderators who were willing to put in time and effort into maintaining a community for free.