world's smallest violin

Etymology
A version of  on violin was used in many melodramatic films in the early 1900s. From this and the use of other violin pieces in melodramatic films derive the term, the phrase break out the violins (in a dismissive/sarcastic show of sympathy), and the image of a violin (small, to reflect that the woe complained of is perceived to be small) playing Hearts and Flowers or "the world's saddest song" in response to complaints of woe.

Noun

 * 1)  A notional violin that plays tragic music for the afflicted; used in dismissive responses to complaints of woe.