I moderate my boyfriend's gaming stream chat, and used to moderate a furry forum. I think on an MLP forum like this things might be fairly calm, but my experience has been a little grating.
When my boy was part of a charity streaming event, some people came into the chat and started spamming inappropriate links and just generally being lewd and disruptive. It's not too uncommon to find people who think ruining the chat for everyone is funny. I'll be the last person to say mischief isn't wonderful, but sometimes I'm not sure if the perpetrator is an 11-year-old who just discovered the word "dicks" or not. When people show up looking to troll or otherwise be a tawdry little deviant, it's the moderator's job to clean up - and sometimes there can be quite a few of them.
On the forum, we had a very loose set of rules and it was mostly self-governing except for when it came to things like genuine harassment, underage porn, etc. Most anything went, and if you didn't like how someone was talking to you then the suggestion was to block them or simply stop participating in discussion with them. However, one guy would send in maybe dozen or more reports a week every time someone so much as called him an idiot. He wildly derailed over 30 threads in the time I was on staff, and our moderator team of 3-4 had to wade through his weekly deluge of reports to get to what could potentially be real problems (we did have a few).
I've also known people to take issues with moderators and complain about favoritism, bias, etc. It's enjoyable enough if you really like working for your community, I guess, but it's not a power position or anything (at least not off of sites that have a horrible reputation for their crazy moderation).