Rtron said
People who go, 'Oh, I'll post in this collab/RP tomorrow!' and then proceed to post in literally everything BUT what they said they would all throughout the following week(s).
I refer to these people as scourges. It's particularly bad when another player's character is mid-interaction with theirs. Destroys RPs, that.
Left an RP recently due to similar behaviour from a GM. They didn't post for ages, when everyone was waiting for clarification on things. I suggested someone else host the RP, assuming the GM had done a runner on us, then he/she suddenly (surprise, surprise) returned to the thread in a whirlwind of rage.
They cried the whole 'oh I'm so busy cus school' thing that's so common on here, but when I checked their post history it appeared they had plenty of time to post in other threads. I've seen that kinda crap so much on here, and it's got to the point now that if I sense that's the kind of person I'm dealing with, then I up and leave. Otherwise I risk being tied to a ship with no captain, also known as: a waste of my frickin time.
Seriously, if you're hosting an RP, decide BEFORE putting it up whether or not you're too busy.