The Possibility Quotient - I like my SF with a dose of possibility

I've been reading some recently-published short stories in the last few days, doing my market research again.  I know we're all supposed to know what's being published in our genre right now, but really sometimes I do wonder why I bother.

Ive read a few stories lately that had SF settings, but were really pure fantasy.  I know the boundaries of speculative fiction are fluid, and I know that any sufficiently advanced technology is indistinguishable from magic, but there are still limits.  And one of those limits is evolution, and the ability of organic life to adapt to new things in its environment,

I have a hard time believing that a human will ever be able to change their skin colour every day.  Our human bodies just aren't adapted to produce blue or green skin, and certainly not to change colour every day.  My guess is we'd need completely different body chemistry to do that.  Unless we bioengineered humans to have chromatophores to move pigments around, like chameleons do.

I guess what I'm saying here is that I run the stories I read through my PQ meter.  My Possibility Quotient meter.  I don't mind advanced tech working in magical ways, but I do mind stories where humans do things they're not evolved to do.

The Possibility Quotient is why I can't get on with so many of the stories I read.  Some of them seem like a five year old's thoughts.  "What about a story where humans have sky blue pink spots and fly on a dragonfly's gossamer wings?"  Not unless the creature is a awful lot lighter than a human.  Or on a planet with a thicker atmosphere than Earth's.  Otherwise they're going to be too heavy for their wings and will break them.

Maybe there's a story somewhere about a flying species coming to Earth, breaking its wings, and not being able to fly again.  That would have high PQ.  But it's the stories without high PQ that get me annoyed.

After all , you don't have to use the trappings of SF to tell your story.  You could move over into fantasy, or magical realism instead.  Yes, the boundaries are blurry, but there's a point at which I think "this is supposed to be SF, and it's doesn't work."  Beware the Possibility Quotient.