"Sometimes the only reason we smile is to keep ourselves from crying."

Everypony in Ponyville knows Derpy Hooves, their friendly, cross-eyed and clumsy but reliable mailmare, a hard-working single mother who is never seen without a smile. For years, she and her family have been residents of the small town, and yet she has never once spoken of where she came from or what she did before her job with the Ponyville Post. Most ponies have simply written such things off over time as curiosity gives way to routine. Some, however, have started to notice just how strained the seemingly happy Pegasus' smile is becoming.

(Gore tag added as a precaution for implication rather than explicit description)
(A huge Thank you! to both Bad_Seed_72 and my brother Corwin for pre-reading this for me)