Coming up with stories, easy and fun.
Collaboration with others, exciting!
Backstories and other stuff, love it.
Adjusting constantly to changing social norms and various mannerisms? Frustrating. Very frustrating. Its like joining a new click, very difficult to find your place, especially when that group has been close for a time.
Sadly, those are the rp's that last are the ones where folks are dedicated to each others ideals and reactions.
Something that's amazing to be a part of but horrendously difficult to not come across as a bitch or silently back out when you're on the outside of it.
/endrant :)