Click the horse repeatedly — glasses included — before you feed it the carrot.
Official in-game clue: "Something wiggles! One click may not be enough."
Where: Day 1 Morning, in the courtyard, the very first scene of the game.
Why it gets missed
Two reasons, and they compound.
There is no feedback until the threshold. You click the horse, nothing happens, and you reasonably conclude the horse is scenery. The clue says one click may not be enough and it means considerably more than one — keep going well past the point it feels pointless.
The carrot closes the window. Feeding the horse is the obvious interaction and it advances the scene. Do that first and the achievement is gone for this playthrough.
What to do
- Before touching the carrot, click the horse over and over.
- Include its glasses — they are a separate target.
- Continue until it visibly reacts.
- Then feed it the carrot and get on with paying the driver.
Other persistence achievements
This is one of a small family that all work the same way: keep clicking, no feedback, then it fires. The others are chasing the crow in the attic, dusting past the third painting, and the rope in the Day 3 dining hall.
Nearby
The full list of hidden achievements, in the order you reach them, is on the triggers page. Going for everything in one run? See 100% completion.