> Does that not mean that every grateful person acknowledges God's existence, at least implicitly?

No. It means that the emotion of gratefulness isn't always a simple reduction to what you have there. Similarly, I think thwave who replied to you is also wrong. The emotion doesn't have to always follow such a simplified framework or be legibly caused. Of course it has to have some causal chain, but I think the legibility could be as opaque as "X is grateful for Y because Z suggested that maybe they should be" where Z didn't have anything to do with Y, Y doesn't necessarily do much for X, and so on. It doesn't make the emotion of gratefulness any less valid. I expect the ways the emotion could come about is varied enough to avoid these simplifications.

Actually, it depends on if there is free will, which by definition is supernatural, else we have as much choice to be grateful as a rock.

Unless gratefulness is actually binary (x is grateful for y), and directing this gratefulness towards someone is completely optional. (One might argue that the object of gratefulness is optional as well, and you can be grateful simpliciter, in an unqualified way. But to them I'd say there's an implied, general, object: the world, life, existence, or something like this.)

> That second SOMEONE is the one that the being grateful is directed at, as they are responsible for things being the way they are. (Being grateful to anyone not causally connected to what one is grateful about seems most weird.)

How does one go about (accurately) decomposing causality in a system this complex and poorly understood though?

This is also good point. Maybe the following paragraph can help. "causes is the two things coming together or being together, which is called ‘association;’ they suppose the two things cause one another. Also, since the non-existence of one thing is the cause of a bounty’s non-existence, they suppose that the thing’s existence is also the cause of the bounty’s existence. They offer their thanks and gratitude to the thing and fall into error. For a bounty’s existence results from all the bounty’s conditions and preliminaries. Whereas the bounty’s non-existence occurs through the non-existence of only a single condition.

For example, someone who does not open the canal to water the garden is the reason and cause of the garden drying up and the non-existence of bounties. But the existence of the garden’s bounties is dependent on hundreds of conditions besides the man’s duty and the bounties come into being through dominical will and power, which are the true cause.

Yes, ‘association’ is one thing and the cause is another. You receive a bounty, but the intention of a person to bestow it on you was the ‘associate’ of the bounty, not the cause. The cause was divine mercy. If the man had not intended to give you the bounty, you would not have received it and it would have been the cause of the bounty’s non-existence. But in consequence of the above rule, the desire to bestow cannot be the cause of the bounty; it can only be one out of hundreds of conditions.... from meaning of Quran "

And a system founded on a complete misunderstanding of the ternary operator

> That second SOMEONE is the one that the being grateful is directed at, as they are responsible for things being the way they are. (Being grateful to anyone not causally connected to what one is grateful about seems most weird.)

It is also common to be grateful to <SOMEONE> for <ATTRIBUTE>. For example, I'm grateful to various people for who they are, by which I mean their worldview, their values, and their personality. Generally speaking, these aspects are not under full control of the individual -- they are the result of a complex interaction of their genetics, their experiences, their intentions, their opportunities, their choices, their habits, and much more.

> Does that not mean that every grateful person acknowledges God's existence, at least implicitly?

I'm not following.