The headlines are full of grim stories about social media (did you read the one about Facebook being used to incite genocide?), as well as expert hand wringing about what the internet is doing to our democracy and mental health. But it's not just agitated professors and human rights activists who are worried. Some of the country's most prominent billionaires are voicing concerns too.

Elon Musk, Jeff Bezos, and Instagram founder Kevin Systrom are among the smartest, most forward-thinking technologists around, so you might expect them to be more optimistic about the internet than the average bear. But recently all three publicly aired serious misgivings about social media, and what's worse for the likes of Facebook, they were all different grievances.

Musk fears social media envy

Most headlines about Musk's appearance on Joe Rogan's podcast last month focused on the Tesla and SpaceX boss's on-air marijuana smoking, but while passing a joint Musk also made some non-stoned sounding comments about how social media wreaks havoc with our mental health.

"One of the issues with social media is people look like they have a much better life than they really do," Business Insider reports Musk saying. "People are posting pictures of when they were really happy, they're modifying those pictures to be better-looking. Even if they're not modifying those pictures, they're selecting the pictures for the best lighting, the best angle."

That's understandable (who wants to post the squinty picture where you look like you have a double chin?), but in the aggregate it creates a situation where everyone's online life ends up looking way better than their real life. The result is unfair comparisons and envy.

Looking at everyone else's hyper curated online life can make people think, "I'm not that good looking and I'm not that happy. So I must suck," Musk warns. "In fact, those people you think are super happy -- actually not that happy. Really depressed, they're very sad." 

Both heartbreaking anecdotal evidence and science back him up that social media is a dissatisfaction machine.

Bezos is worried about information bubbles

Jeff Bezos, meanwhile, is concerned it is also a "confirmation bias machine." The Amazon boss, who is on the record highly valuing intellectual humility and curiosity, is worried social media is cocooning us in information bubbles.

"I think the internet in its current incarnation is a confirmation bias machine. I worry that some of these technologies will be very useful to autocratic regimes to enforce their will," he warned at the Wired 25 conference this week.

But while exposing ourselves only to information that supports our existing views makes us easier to lead (and easier to lead astray), Bezos is optimistic we'll figure out how to fight back against this problem.

"The book was invented and people could write really evil books and lead bad revolutions with them. And create fascists empires with books. It doesn't mean the book is bad," he noted. "Society develops an immune response eventually to the bad uses of new technology, but it takes time. ... We will figure it out," Let's hope it doesn't take a few hundreds years of war to manage it this time around.

Systrom says privacy is his top concern

Finally, speaking at the same conference, Systrom, who recently parted ways with Facebook, took a subtle swipe at the company that acquired Instagram. His complaint wasn't misleading information of either the personal or political variety. It was lack of user control.

Currently, Facebook controls what information users see. Systrom believes that users should control what content users see.

"Instagram rolled out controls in the last year giving users the ability to shut down comments on their photos, selectively block words and groups, and other granular adjustments," reports Quartz. Systrom noted that, while these tools may cut down the amount of time people spend on the app, the loss of engagement was a trade off worth making in the long run. It's unclear whether Mark Zuckerberg agrees with him.

What this means for you

Each of these critiques of social media is fascinating individually, but taken together they suggest that social media faces a whole constellation of vexing problems. It also suggests that individual users need to think critically about their use of these tools. One computer science professor suggests a 30-day social media detox is the best way to get clarity on what uses of social are adding value to your life and which aren't.

These comments also suggest there may be big opportunities out there for entrepreneurs who can figure out how to do social media better. Top VC Fred Wilson speculated as much in a recent blog post, and no less an impressive figure than the internet's inventor, Tim Berners-Lee, is hard at work on new technology to save the internet from itself.