One day, Pinkie Pie asks Derpy about her past. What she found out made her want to make the mailmare even happier than she had made anypony before.
Derpy Hooves is a nopony, as far as she knows. She has little to nothing to look forward to in her life, and that was something that she was fine with.
Pinkie Pie is the ultimate friend for anypony to ever have. She`s almost like a sister to any of her friends. When she asks Derpy an important question, she decides to make Derpy happy in a very special way.