I don't know if I speak for anyone besides myself with what I'm about to say, but here goes:
When I write, it's because I enjoy creating things. Characters, settings, stories, all of that and more. However, as much as I enjoy RPs because of the immediate feedback and sense of mystery and anticipation in what the other people will write, they always pose a problem in terms of motivation for me because of the reasons I just gave for writing at all. I don't know if any of you know me well enough to have noticed this already, but I'm a very easily intimidated person. I started RPing when I was very young and immature, and as a result made some very stupid decisions that I don't like to think about and I now know drove some people up the wall. The problem is, no one came out and told me back then that I needed to get it together and act more maturely. Instead, they badmouthed me behind my back. It was ultimately a good thing because it made me more self-aware, but it has also made me very insecure when it comes to "rocking the boat", so to speak.
Now, whenever a cool idea comes to me that would otherwise motivate me to share it through posting, I start to get nervous instead. "You'll re-read that tomorrow and think it's stupid." "You're being self-centered, no one cares but you." "You don't have the authority to put that forward." If I go silent for a long time, sometimes it's for real life reasons, but other times thoughts like these are weighing me down. I know it's mostly just my stupid brain, but I usually feel as though I have no control over the story of an RP and my character(s) are completely insignificant, and when the excitement of something being "new" is gone, it's all I'm left with. Maybe it would help if power over the RP's direction was spread around more.
Edit: Honestly, I'm wondering if this should be RWBY anymore. A good number of people here seem to feel negatively about it, and most of its influences are either superficial (color names, generic "monster" enemies, semblances that could honestly just be super powers) or hindering (four person teams, missions that need to be "completed").