What's the big deal about a giant rotating ball? What's the big deal about the universe? What does it have to do with anything?
Life can be as important as you choose for it to be, just as can the universe. To a scientist, the universe is so important to the extent of deserving fascination and awe and a life's research. To a construction worker, who cares. I guess you could say those are "little things" (careers, interests, etc.) that could matter depending on yourself and the role you decide to play in the world, but of course, in the grand scheme of things, how relevant is "meaning" anyway? Science and evolution and all that junk will tell you that the meaning of life is to survive and reproduce. I think that's nonsense. Call me crazy.
So other than yourself choosing a miniscule detail of life to attribute meaning to, I don't see how meaning can mean anything. "Meaning" is what fulfills something for you mentally. If you can not be fulfilled mentally, perhaps you are depressed. Nothing is stimulating enough and nothing is fascinating. I get that.
Humanity is overrated a tad, so I guess I could concede to that. Everything's pretty overrated now that I think about it.
That's just depression. Nothing is fundamentally meaningless or meaningful. It all depends on the situation.
Natural instincts, hmm, I wonder what you mean by that. Can we have unnaturally created something unnatural? I think it's a redundant discussion but it could still go into a few details.