I'm gonna say Market Squad.
The Market's pretty much filled with idiots.
Idiots who can't read rules, idiots who read rules so that they could find loopholes and abuse them so much that Josef Fritzl would be jealous.
And a lot of other kind of idiots and other kind of annoying stuff that would drive any normal human being insane.
Market Squad has to moderate ALL this, while they get thousands of complaints about "unfair" infractions and bans and just some random people hating them because of the same "unfairness".
Among that they have to deal with tons of scams and account thefts.
And I don't think they get that much of gratitude from what they do.
Yeah, GameKeepers make lots of fun stuff for the community and ToriAgents get us new meat players, and I respect their work, but still they're like ants' poop compared to Market Squad, which would be elephants' massive (and smellier) shit.