Applejack abandons her pie deliveries out of worry and goes back to check on her little sister who's home alone. As a result, she winds up acting extremely over-protective to Apple Bloom, to the point of stalking her.
But what if, instead of sneaking out to make the pie deliveries herself, Apple Bloom snapped and said something in a fit of anger that cut deep into her sister's soul?
An alternate take on Somepony to Watch Over Me