Are you thinking of a faulty description of science methodology, or of insufficiently explained impossibilities?
Mostly the former, though with the latter it'll depend on... sorry this is handwavy... how much I can trust the author. You can get away with a
lot with a sufficiently compelling character and voice.
And, here's a Clarion moment, one of the instructors said science fiction is about the edges of technology, the various effects it has, rather than about the tech itself. So what's interesting about cell phones is not how they work, but the ir effects on the culture. So for example, you can't tell the crazies talking to themselves from the people on earbud cellphones any more. And you have to go a long way into the mountains before you can really get lost and not be able to call home. And the obvious thing to do in a dark city street where you're being stalked by a werewolf is now to call 911.
And, for example, during the southern california wildfires when the govmint instituted a reverse-911 call to warn people, they needed a website where you could enter your cell phone and address. Or they couldn't have gotten to most people, because area code and actual location aren't necessarily connected any more, and some people have no home phone number.
If I can explore the effects of technology, while reading, better than the author does, then I lose faith.
You as the author need to know at least ten times as much as you will explicitly mention in the story -- about the setting, about the science, about the culture, about the characters, about everything.
I think this is what lets you figure out those spreading effects that are so interesting
However, you do need to know (but probably still won't have any reason to mention) how a car "works". You need to know it can't do 500 MPH or travel 2000 miles between fill-ups or hold 150 passengers or tow 10 tons or drive across the bottom of a lake. You also need to know that most developed countries have rules about who can or can't drive a car and where the cars can or can't be driven and specific procedures to follow when driving. Your story would be pretty absurd if you wrote a scene violating any of that.
And you need to know that when things are spread out, people tend to have more cars, so there are traffic jams which affect people's temper. And you might have to hunt for parking spaces. (And there
are parking spaces; imagine a world with cars and no parking, because the author hadn't thought it through) The end result is that cars aren't always going at top speed.
The strictest definition of science fiction is that the author is allowed to make one assumption contrary to known science but must work out the consequences of that assumption with scientific rigor.
Ah so, this is close to what I was saying, I think. I'd say you need narrative rigor rather than scientific rigor -- the sciences often think more precisely and less broadly than you'd want
Of course, the proper science is also important. I am a lab technician with an environmental studies degree, but I doubt my ability to test water for toxins will help me understand how to put together an android
But so long as your story isn't about putting an android together, it doesn't matter. So long as you figure out sort of how they work, and then the consequences of that.
You ever heard of someone named Asimov? That was a PhD in chemistry he had. And he is not the only one by a long shot. Many of the big names in SF have had scientific backgrounds of one kind or another. What that means is that they have a respect for science being represented in fiction and expect a good deal of verisimilitude. It has to be something that in some stretch of the imagination COULD work.
Yes, but Asimov seldom wrote about biochemistry (which was his field). And I've talked to Vernor Vinge, who has a PhD in mathematics, and says there's a really good reason he writes about things entirely outside his field. Because a mathematician writing about math is only going to appeal to mathematicians; a lay person's understanding would be boring to the mathematician, and vice versa.
And more to the point, I suspect, nobody's accusing Douglas Adams of having been a rigorous scientist, are they? That seems closer to the OP's intent than serious hard-sf is.