Le vrai goût des émotions

You'll need to use the emo-dial to change an NPC's emotion to all 4 possible emotions, including their original starting emotion.

This achievement has no cultural references in the English and Chinese versions. It is likely specific to the game. The Trailblazer uses their Clockwork ability to make people taste/savor other emotions, should they be missing one or forcing themselves to only ever feel one.