Applejack and Fluttershy have never been particularly close; in all honesty they're more like acquaintances with mutual friends than actual friends with each other.
But when Winona is injured Fluttershy is the only one who can help, and as Applejack tries to pay back the debt she feels she owes the pegasus for her kindness they both discover that there might be more to each other, and their own feelings, than they realized.

Cadence runs into Celestia while she is waiting for Shining Armor, and what starts out as an everyday conversation quickly becomes something else when Cadence reflects upon the heritage that both made her an alicorn and shaped the course of her life.