That little omission is revealing. Could it be that you believe you are more than the sum of your neurological parts?
... well, ...
Brains are just lumps of matter.
That little insertion is revealing. What you meant to say was:
Brains are lumps of matter.
By saying that brains are lumps of matter, you're describing what we know. By saying that brains are "just" lumps of matter, all you're doing is injecting something you don't know that, by your particular mode of analysis, you couldn't possibly know; i.e., you shouldn't say "just" in this context because there's no way you can back it up.
We know matter exists because we're thrust into this world, and we find it, classify it, and categorize it. We know what matter can do because we look at it, poke it, and figure out what it does. Apparently, matter can do some fascinating things.
Some rote capabilities of matter are to simply have weight--I can use a sufficiently heavy (but not too heavy) conveniently sized solid object of any constitution as a door stop. Matter can also display written text--that's kind of cool. Some matter in my house can transmit written text to people across the world through a wire that runs into my wall. That is incredibly cool. But it gets even better--there are some lumps of matter that I have that can transmit sound and pictures of my nephews/nieces in real time many thousands of miles away to me, without even going across any wire!
Obviously you know of technologies like this, because we're not in a stone age, but the major point here is that these things really do have capabilities one can only describe as "magical", and the only way we really know about these capabilities, besides this strange group of priests and cultists who preach that there exist such things, is to actually get ahold of one and look to see that it can, indeed, actually do those things. This is so commonplace that we're not bothered at all by claims that matter can send my voice and pictures to another part of the country... I expect no sane person on this forum to refute this (and if they do, I suspect it's much more likely they're a troll).
Now, rocks can't transmit video pictures to me or voice across vast distances in real time. Neither can suns. My wireless cam and mike can do this though. But I suspect that they do it via technologies--transmitting signals across the air using electromagnetic waves to the cool blinkenlight thing wired into my wall, which is kindly transmitted to an arbitrary location of my choosing for a nominal fee by a local company.
Now if we consider, instead of these technological gizmos, some natural lumps of matter--such as this cute thing that runs around in my yard that appears to have made a residence under the steps--then it can do some fascinating things as well. It appears, to me, that this thing likes acorns. I'm just saying, that's what it looks like--and just as I think my camera can transmit videos across the country, I think this cute fuzzy lump of matter can like things.
So when you say:
Lumps of matter don't like or dislike things.
...then I'm suddenly curious. Do you not have cute fuzzy things in your yard that gather acorns?
They're just colletions of stuff.
That's partly true. That rock, that sun, this desktop, this wireless device, and that thing that has made a residence under the steps on the side of my house, are all collections of stuff. But none of them are "just" collections of stuff. They are really cool collections of stuff that can do fascinating things. I don't relegate their lack of capabilities a priori, I just look at them, and believe they can do what they seem to be doing.
Does a rock like rolling down a hill, or a star like producing energy?
Nope. Neither do they transmit video and pictures to my nephews and nieces thousands of miles away in real time. The cute fuzzy thing that has taken residence under the steps outside can't transmit video and pictures to my nephews and nieces thousands of miles away in real time either, nor can my wireless device like things. Apparently different arrangements of matter can do different things.
The materialist story is that when you arrange specific matter in a specific way (i.e., a brain), it can like and dislike things.
That seems to be the case. That cute fuzzy thing sure does seem to like nuts. It dislikes me, however, which is a pity; makes it really hard for it to stay still long enough to capture it on video (with my wireless device).
How is this possible? How does it work?
Don't know exactly; unfortunately, the fuzzy thing that takes residence under the steps wasn't made by engineers that talk English (or some language that translates into it), so we have to wait until the reverse engineering is complete. But a lot of it has been done. I could tell you some of the details of how those pictures get transmitted to my nephews and nieces in real time if you want to hear it.
Why are some lumps of matter capable of subjective experience and all others not?
At the high level, for the same reason that fuzzy thing that takes residence under my stairs, the rock, and that sun cannot transmit video to my nephews and nieces thousands of miles away in real time. Some arrangements of matter apparently cannot do what other arrangements of matter can.
What is the missing ingredient?
In terms of having a subjective experience, one notable missing ingredient is a subject. To have a subject you need an agency. Agencies of the sort we know about are entities that have collaborative planning capabilities, and represent the world in terms of world models. They have sensory apparatuses which perform a lot of very complicated work in order to come up with high level representations in those world model terms, which then get "tossed" into the collaborative planning entities' workspaces; we call such things percepts. The entire set of collaborative perception and planning (by which I include actions here) capability is the agency. Some such agencies reflect affinities to certain categories of represented real world objects, which they can recognize by percepts generated by their senses; we call that "liking".
The answers are either non-existent, highly speculative (magical, if you will), or lead to idealism (everything is conscious).
Or are based on observation, and no a priori rejection that matter is "just" matter and "cannot like things".