Okay, so Rainbow Dash steals a bullshit stone to use on Fluttershy because she's jealous Fluttershy is skinnier than her?
I guess Rainbow must have gotten drummed out of all her jobs, forced to mooch on Fluttershy, and then slowly start to hate Fluttershy for her apparent successes.
Nah I'm just reading too much into it. Except for the Bullshit Stone. That's canon.