Being a Wonderbolt doesn't mean you're infallible. It doesn't mean you always have to win no matter what. It does mean, however, that you have to set an example for other ponies to follow.

Spitfire doesn't feel like she did that at the Equestria Games tryouts. Even though her intentions weren't as callous as they appeared, she still feels awful about doing wrong by Rainbow Dash and Soarin'. Luckily, she has a great team that will hear her out even when she screws up.

My mini-epilogue to the episode Rainbow Falls.