Children are monsters. Annoying, selfish monsters. This could easily be a screenshot of an episode dealing with how people hurt each other, and how hard it is to get friends back after an offense.
Visually, this is a treat. The composition is simple, and elegantly leads the viewer from Sweetie Belle to the bag to the other two. The action lines on Apple Bloom and Scootaloo form a huddled A shape with the book. The backgrounds are clutter-free, and the circle on the floor symbolically isolates the two from Sweetie Belle.
The characters are well drawn, and on-model. The blush and the eye dilation on Sweetie Belle are perfect.
The book text required a click to zoom to read, but that's okay because it heightened the drama. The only things I think could use work are Sweetie's right hind leg and Scootaloo's left; the hooves on both are not quite on-model, IMO.
A stunning piece, which could easily be the cover to an MLP:FiM comic book.
: Apple Bloom, you're grounded! No crusading, no playtime, and no supper! : I'm sorry, Applejack! It won't happen again! I promise : As for you, kid, we're going to have a talk with your parents! You're going to get a lecture! That was totally UN-COOL! : I didn't mean to, Rainbow! I'm sorry!