expression
why; how come
Emphatic, lamenting, or sarcastic rhetorical question. Often followed by なければならない or similar expressions to express frustration about an obligation.
何が悲しくてこんなに働かなければならないんだ。
Why on earth do I have to work this much?
何が悲しくて休日に早起きしなきゃいけないの。
Why in the world do I have to get up early on my day off?
expression
Used as a lamenting interjection, expressing regret or disappointment about a situation. Often stands alone or at the beginning of a sentence.
何が悲しくて、財布を落としてしまった。
Alas, I dropped my wallet.
何が悲しくて、また雨か。
Unfortunately, it's raining again.