Don't really have any specific RP sessions running right now or anything, so there's no need to bitch about the usual "other people not having the same level of commitment" problem I tend to run into whenever I actually get into some proper RPing.

I guess if I'm gonna put down anything, it'd be that, from my own experience, the most frustrating situation a GM can ever be put into is trying to set up RPs when they involve an original setting that isn't created only for the purposes of RP but also to be an official work in and of itself. This takes far more time, and is far more difficult, than GMing RPs based off of pre-existent works or a setting that was created solely for the RP session. Inactivity and lack of commitment on the part of your RP partners is an obvious pain in the ass, but this situation is worse in my opinion.