Bedrockgames
I post in the voice of Christopher Walken
What we’re talking about is not an example of the GM not giving a player the outcome he wants. It’s about him denying the entire journey that the player has said he’d like to take.
I’m gonna run with my “Kung Fu” example. Looking for his brother is very far from the only thing that Caine did in the series. He had tons of adventures. But it was his main drive.
Sanbox play isn't usually built around a premise like that. If we were running a monster of the week or adventure of the week campaign (which I do run between sandboxes) and we hashed out an idea that the framework of those adventures was you were looking for your long lost brother, that would be reasonable. But again, in a sandbox game, the decision to go look for your brother, doesn't guarantee what you will find, and it doesn't guarantee you will get a series of adventures along the way. That just isn't the nature of a sandbox game. Maybe you don't like sandbox. That is fine. But I've run enough of them, to know they work, to know this isn't a problem for plenty of groups.