This is based off a couple of things. One is obviously the controversy around Big Mac. The second is the Angst, What Angst entry on Tropes’ YMMV Page.
 
“Unlike the appropriately miffed Apple Bloom, Sweetie Belle shows no outward disappointment about Rarity having to duck out of the games at the last minute. The fact that she had a near-breakdown when Rarity initially refused to participate only makes it more glaring.”
 
And the third bit, the one regarding the map, I based that off a fanfic where Spike voiced his dissent towards the map. “Destiny is…is what somepony else wants for you!”