It's just a movie. Chill. No one ever claimed either of those movies was 100% scientifically accurate, and plot rules all when it comes to fiction. If you need to (and it sounds like you really really need to)
I don't. Stop defending mediocre crap, because that is exactly the attitude that is 100% opposite of what science is all about and the culture that steers people away from it. Science is about critically looking at everything, and being thorough and rigorous.
Imagine all the different types of people on this planet and then decide which groups of people are least likely to utter the phrase "It's just a movie. Chill." It's a small step away from "Don't be such a geek/nerd/grammar nazi."
Anyway, the plots of both Gravity and Interstellar were just terrible and effectively extremely shallow. Honestly, what wisdom or profound thought have they imbued us with? Watch Moon (2009) instead, it is a million times better on almost every level.
It's mediocre crap to you because you're closed-minded. Everything has to conform to your standards. Just enjoy a film for what it is: fiction. If you can't do that, then don't watch them and then complain about them. Just makes you look like an idiot.
No one has been steered away from science because of fiction. Not one of these films has ever made anyone think, "Hmmm. Maybe I'll change my major from Physics to French Military History because the science in that film sucked." You're just being ridiculous.
Who needs profound thought from Sandra Bullock or Matthew McConaughey? I just need to be entertained. I'm smart enough to know what's not real, and if I'm having a good enough time, then I just don't care. And maybe discussion about what's not real in a fictional setting will inspire someone to find out how it would really work and become a scientist/mathematician/whatever. If they're bored with something like, "Well the radiation would really kill him in about three days, so he has to have layers and layers of material that will stop it, so he couldn't do anything interesting at all in this movie because he's basically wrapped up like a mummy...", then they'll be bored with science.
And for the record, I love Moon. And Sunshine. And Gravity. And I'm sure that I'll love The Martian. All for different reasons, and not one of them is Science(!). But you'll hate anything that isn't 100% perfect for one reason. Just go read books or watch videos about momentum and escape velocity and whatever else you feel aggrieved about in these films and you'll be much happier.