偏偏: of all things, stubbornly
副词 / adverbs
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
S + 偏偏 + V (against one's wishes / against reason)
偏偏 says something goes against wishes or reason, often with frustration:
1. Bad luck: "of all times", "just when": 我要出门，偏偏下起了雨.
2. Stubbornness: "insist on": 大家都劝他，他偏偏不听.
偏 alone exists too (more colloquial): 你不让我去，我偏要去！
Examples
我正要出门，偏偏下起了大雨。
Wǒ zhèng yào chūmén, piānpiān xià qǐ le dà yǔ.I was just about to go out when, of course, it started pouring.
父亲希望他学医，他偏偏爱上了写诗。
Fùqīn xīwàng tā xué yī, tā piānpiān ài shàng le xiě shī.His father wanted him to study medicine, but he fell in love with writing poetry instead.
大家都劝她别去，她偏偏不听。
Dàjiā dōu quàn tā bié qù, tā piānpiān bù tīng.Everyone told her not to go, but she stubbornly wouldn't listen.
Common mistakes
✗ 偏偏 for a happy coincidence: ✗ 我想吃饺子，偏偏妈妈做了饺子 → ✓ 正好/刚好. 偏偏 = annoying.
✗ 偏偏他…: standard slot is after the subject, ✓ 他偏偏….