Comparing “fǎn’ér” and “xiāngfǎn”

我以为他会生气，他反而笑了。

Wǒ yǐwéi tā huì shēngqì, tā fǎn’ér xiào le.

I thought he would get angry, but instead he laughed.

他的想法跟我相反。

Tā de xiǎngfǎ gēn wǒ xiāngfǎn.

His idea is opposite to mine.

休息以后我不但没好一点，反而更累了。 / 他说不难，我看法正好相反。

Xiūxi yǐhòu wǒ bùdàn méi hǎo yìdiǎn, fǎn’ér gèng lèi le. / Tā shuō bù nán, wǒ kànfǎ zhènghǎo xiāngfǎn.

After resting, I not only did not feel better, but instead felt even more tired. / He says it is not difficult; my opinion is exactly the opposite.