Like @Odin said, Casual often contains decisions in posts that scratch heads, don't fit, or otherwise feel like they served no meaningful purpose to the larger picture. That and in my own experience (anecdote warning) I often recall seeing decisions that were rather selfish, serving to push one character's story along to the detriment or exclusion of others. Just by being around that I ended up doing it sometimes myself, and I think catching myself doing it is more frustrating than someone else doing it, because I like to think that I can be better than that.
As someone that roleplayed in casual for literally years pre-guildfall, I can 100% agree with this. I've moved onto advanced roleplay ever since and ocasionally dip into casual to GM because muh roleplays need players, and what I think is interesting is when you see this change in people -- for me it wasn't because of advanced roleplay to be honest, but it was a particularly good 1x1 that made me rethink what it means to collaboratively write. Where as before I (as the GM) set certain plotpoints in the ground as a sort of 'checkpoint' and generally did not have much help in that regard (casual roleplayers are nothing if not passive in my experience, and require more handholding than either free roleplayers or advanced roleplayers), this time I was actually, shock gasp horror, plotting very far ahead into the roleplay with my partner and discussing potential situations in the future for our characters to run into.
That's not so special, but what was was that we actually set out to
do those things.I think that's when I stopped writing for myself/my character and started writing to form a more cohesive story around
all the characters (or trying to, I'm arrogant, but not so arrogant as to propose that I am always taking into count everything and everyone) where sometimes my character ends up on the shitty end of the shovel/stick/utensil.
I'm thinking of what could potentially cause this and I think it relates perhaps to the.. fragile nature of roleplays particularly in casual RP. We all know RP's die quick, but I think casual really is one place where they die quicker than anywhere else. Take a week to start the IC, and your players are gone, that kinda stuff. So perhaps players just don't have the time to get attached to the roleplay/the cast as much as they do their own characters. They did, after all, just spend about an hour or so making that character.
I tried something new the other day in a casual RP I hosted where I forced people to come together and discuss some sort of cohesive 'theme' for their team. While the RP still died I think this was pretty succesful in at least tying together
some of the cast by forcing them to come up with a connected backstory or some other tidbit of information that extended beyond 'we were all in the same school a year ago.'
Errr, that was kinda rant-y, but whatever. Have fun decyphering what the fuck I'm trying to say.