As the Traveler returns to Mondstadt after defeating Stormterror, they are greeted by Amber:
Amber: Wait for me at Good Hunter. I'll be right there, I just have to clean up here real quick.
The quest markers instruct the player to
go to the city and talk with some npc (Cyrus, Nimrod and Grace) before going to Good Hunter. They do not mention anything else.
Yet, if you like Amber enough to pretend to help her and
start destroying the barricades she is meant to clean up...
A new objective pops up:
Destroy the hilichurls' barricades (0/13)
Talking to Otto afterwards gives a short dialogue
acknowledging the player actions and a small reward.
Otto: Thanks for helping us clean up the battlefield... You really didn't have to, you know...
Otto: This work ethic of yours really puts me to shame.
Otto: I know this paltry sum doesn't begin to pay you back for everything you've done for the Knights, but... for what it's worth, please take it.
(Gain "Pile 'Em Up" ×3, Adventurer's Experience ×4, Mora ×10,125, Mystic Enhancement Ore ×2, Adventure EXP ×350)
Similarly, the commission "Pigeons Go AWOL"
has an alternate ending that can be unlocked only by doing a specific, unlisted objective at a specific time in the quest (picking up a dropped letter).
Forgetting for a second about commissions where
"failing a quest" opens up an hidden sequel (See: killing pigeons),
Does any other quest feature similar "hidden branches" that produce better or just slightly different outcomes?