This is why when other people on the internet say she's nothing but an arrogant, insensitive show-off, it breaks my heart. Yeah, sometimes she can be all that. But hey, everypony has flaws. But what she did at this moment made me gasp and smile and shed tears almost. Oh gosh I lost it. Her loyalty really shows here because like you said, she realized there are more important things in life than those aspirations. She didn't like what she had to go through to be a Wonderbolt, and gave it all up.
Gosh, Rainbow Dash. You are the best pony ever. If a person ever says anything negative about you, I will laugh in their faces until my ribs hurt.